DRAFT REPORT FOR CONSULTATION
12
3

ICRP ref 4818-2733-7736
May 20, 2011

4

5

Annals of the ICRP

67ICRP PUBLICATION XXX

8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

Patient and Staff RadiologicalProtection in Cardiology
Full Members:

Claire Cousins (Chair)
Donald Miller (Co-Chair)
Guglielmo Bernardi
Madan RehaniPeter Schofield
Eliseo Vano

Corresponding Members:

Bernhard Geiger
Philip Heintz
Renato Padovani
Kui-Hian Sim
Andrew J. Einstein

1

DRAFT REPORT FOR CONSULTATION
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67

Contents
Abstract
Preface
Executive Summary
Recommendations
Glossary
1. Introduction
2. The Biological Effects of Radiation
3. Clinical Examples of Deterministic Injury after
Fluoroscopically Guided Cardiac Procedures
4. Principles of Radiological protection for Patients and Staff
5. Managing Patient Dose in Fluoroscopically Guided
Interventions
6. Radiation Doses and Protection of Staff during Interventional
Fluoroscopy
7. Radiological Protection for Nuclear Cardiology
8. Radiological Protection for Cardiac CT
9. Radiological protection Training for Interventional
Fluoroscopy
10. Quality Assurance Programmes

2DRAFT REPORT FOR CONSULTATION
68

69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111

Patient and Staff RadiologicalProtection in Cardiology
ICRP PUBLICATION XXXApproved by the Commission in Xxxxxxx 20XX
Abstract- Cardiac nuclear medicine, cardiac CT, percutaneous coronary
interventions and electrophysiology procedures are increasing in number andaccount for an important share of patient radiation exposure in medicine. Complex
percutaneous coronary interventions and cardiac electrophysiology procedures areassociated with high radiation doses. These procedures can result in patient skindoses high enough to cause radiation injury and, in children, an increased risk ofcancer. Treatment of congenital heart disease in children is of particular concern.
Additionally, staff in cardiac catheterization laboratories may receive high radiation
doses if radiological protection tools are not used properly.
The Commission has provided recommendations for radiological protection
during fluoroscopically guided interventions in ICRP Publication 85, forradiological protection in CT in ICRP Publications 87 and 102, and for training inradiological protection in ICRP Publication 113 (ICRP 2000a,b, 2007, 2009). This
report is focused specifically on cardiology, and brings together information relevant
to cardiology from the Commission‘s published documents. There is emphasis on
those imaging procedures and interventions specific to cardiology. The material andrecommendations in the current document have been updated to reflect the mostrecent recommendations of the Commission.
This report provides guidance to assist the cardiologist with justification andoptimization of cardiac CT studies, cardiac nuclear medicine studies andfluoroscopically guided cardiac interventions. It includes discussions of thebiological effects of radiation, principles of radiological protection, protection ofstaff during fluoroscopically guided interventions, radiological protection training
and establishment of a quality assurance programme for cardiac imaging andintervention.
Because tissue injury, principally skin injury, is a risk for fluoroscopicallyguided interventions, particular attention is devoted to clinical examples ofradiation-related skin injuries from cardiac interventions, methods to reduce patientradiation dose, training recommendations, and quality assurance programs forinterventional fluoroscopy.
© 2011 ICRP Published by Elsevier Ltd. All rights reserved.
Keywords: Cardiology, Computed Tomography, Nuclear Medicine, Cardiac
Catheterization, Radiological Protection

3

DRAFT REPORT FOR CONSULTATION
112

PREFACE

113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

Over the years, The International Commission on Radiological Protection (ICRP)
referred to below as ‗the Commission‘, has issued a number of reports that provide
advice on radiological protection and safety in medicine. ICRP Publication 105 is a
general overview of this area (ICRP, 2007a). These reports summarize the generalprinciples of radiological protection and provide advice on the application of theseprinciples to the various uses of ionising radiation in medicine.
Some previous reports have dealt in part with issues relevant to cardiology andhave appeared in print as Publications 85, 87, 102 and 113 (ICRP, 2000a,b, 2007b,2009) and Supporting Guidance 2 (ICRP, 2001). The present report continues thisseries of concise and focused documents.
In cardiology, patient radiation exposure is due to nuclear medicine, CT,
percutaneous coronary interventions and electrophysiology procedures. This rapidly
expanding field of medicine, both in numbers and complexity, requires guidance forpractitioners.
At their meeting in Beijing in 2004, the Commission decided that there would bevalue in developing guidance on radiological protection for cardiologists. Due to avariety of other priorities, work on the document was interrupted for a time andresumed in earnest in 2010.
The membership of the Task Group was as follows:
C. Cousins (Chair)
M.M. Rehani

134
135
136

143
144
145
146
147
148

G. Bernardi(1) E. Vañó

Corresponding members were:(2) B. Geiger
K.-H. Sim

137
138
139
140
141
142

D.L. Miller (Co-Chair)
P. Schofield

P. Heintz
A.J. Einstein

R. Padovani

In addition, Jacques Lochard and John Boice, Main Commission members, madeimportant contributions as critical reviewers.
The membership of Committee 3 during the period of final preparation of thisreport was:E. Vañó (Chair)
J.M. Cosset
J.W. Hopewell
S. Mattson

M. M. Rehani (Secretary)
L.T. Dauer
P.-L. Khong
D.L. Miller

H. Ringertz
B. YueM. Rosenstein

M.R. Baeza
I. Gusev
P. Ortiz López(3) K.
RiklundY. YonekuraÅhlström

References
ICRP, 2000a. Avoidance of radiation injuries from medical interventional
procedures. ICRP Publication 85. Ann. ICRP 30 (2).
4

DRAFT REPORT FOR CONSULTATION
149
150
151
152
153
154
155
156
157
158
159
160
161

ICRP, 2000b. Managing patient dose in computed tomography. ICRP Publication
87. Ann. ICRP 30 (4).
ICRP, 2007a. Managing patient dose in multi-detector computed tomography. ICRP
Publication 102. Ann. ICRP 37 (1).
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann.
ICRP 37 (6).
ICRP, 2009. Recommendations of the International Commission on RadiologicalProtection. ICRP Publication 113, Ann. ICRP 39 (5).
ICRP, 2001. Radiation and your patient – a guide for medical practitioners. ICRP
Supporting Guidance 2. Ann. ICRP 31 (4).

5DRAFT REPORT FOR CONSULTATION
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210

EXECUTIVE SUMMARY
In cardiology, patient radiation exposure is due to nuclear medicine, CT,
percutaneous coronary interventions and electrophysiology procedures. Cardiac
nuclear medicine, cardiac CT, percutaneous coronary interventions andelectrophysiology procedures are increasing in number and account for an important
share of patient radiation exposure in medicine. Complex percutaneous coronary
interventions and cardiac electrophysiology procedures are associated with highradiation doses. These procedures can result in patient skin doses high enough tocause radiation injury and, in children, an increased risk of cancer. Treatment ofcongenital heart disease in children is of particular concern. Additionally, staff in
cardiac catheterization laboratories may receive high radiation doses if radiologicalprotection tools are not used properly.
1. The Biological Effects of Radiation
Stochastic effects are malignant disease and heritable effects for which theprobability of an effect occurring, but not its severity, is regarded as a function ofdose without threshold. The likelihood of inducing a stochastic effect increases with
dose, but the exact relationship between dose and effect is not known. Children areapproximately 2-3 times more sensitive to the stochastic effects of radiation thanadults. They also have a longer potential lifespan than do adults, so they have moretime to develop possible radiation related sequelae.
Deterministic effects (e.g., skin injury) are due to injury in populations ofcells, characterised by a threshold dose and an increase in the incidence and severityof the reaction as the dose is increased further. Deterministic effects are also termed
tissue reactions. Radiation-induced skin injuries may not become fully manifest untilmonths after the radiation dose was administered. The diagnosis of a radiationinduced skin injury is often delayed. Deterministic injuries may extend into deeper
tissues and can cause symptoms that persist for years. Deterministic injuries may be
accompanied by an increase in stochastic risk.
The mechanisms of heart radiation damage include inflammatory processes, inparticular after low doses, and after higher doses there is a progressive reduction in
the number of patent capillaries eventually leading to ischemia, myocardial cell
death and fibrosis, accelerated atherosclerosis in major blood vessels, decreased
cardiac function, and fatal congestive heart failure. Cardiovascular radiation effects
have been reported to occur at doses > 0.5 Gy. Organ doses may reach this level insome complex fluoroscopically guided cardiac procedures.
The lens of the eye is a radiosensitive tissue. Ionizing radiation typicallycauses posterior subcapsular cataract formation in the lens of the eye. Surveys ofcardiologists and support staff working in catheterization laboratories have found ahigh percentage of lens opacities attributable to occupational radiation exposure
when radiological protection tools have not been used properly.
2. Principles of Radiological Protection for Patients and Staff
The Commission recommends three principles of radiological protection:
justification, optimization of protection, and application of dose limits (ICRP, 2007).
The first two are source related and apply to all radiation exposure situations. The
6

DRAFT REPORT FOR CONSULTATION
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258

third applies to staff, but does not apply to medical exposures of patients or to carers
and comforters.
Justification means that a medical procedure should only be performed when it
is appropriate for a particular patient— the anticipated clinical benefits should
exceed all anticipated procedural risks, including radiation risk. For CT and nuclear
medicine studies, justification is a responsibility shared between the referring
clinician and the cardiac imager. For fluoroscopically guided interventions, theresponsibility rests with the interventionalist.
Optimization means that the radiation dose to the patient is suitable for the
medical purpose, and radiation that is clinically unnecessary or unproductive is
avoided. Patient radiation dose is optimized when imaging is performed with theleast amount of radiation required to provide adequate image quality, diagnostic
information, and for fluoroscopy, adequate imaging guidance.
3. Managing patient dose in fluoroscopically guided interventions
The informed consent process should include information on radiation risk if
the risk of radiation injury is thought to be significant. Important aspects of thepatient‘s medical history that should be considered when estimating radiation risk
are genetic factors, co-existing diseases, medication use, radiation history, andpregnancy.
Some of the factors that affect the patient‘s radiation dose depend on the x-ray
system, but many others depend on how the operator uses the x-ray system. During
the procedure, the cardiologist should be kept aware of the fluoroscopy time, thenumber of cine series and cine frames, and the total patient dose. As patientradiation dose increases, the operator should consider the radiation dose alreadydelivered to the patient and the additional radiation necessary to complete theprocedure.
Patient radiation dose reports should be produced at the end of the procedure,
and archived. Radiation dose data should be recorded in the patient‘s medical
record after the procedure. When the patient‘s radiation dose from the procedure ishigh, clinical follow-up is essential for early detection and management of skin
injuries. Patients who have received a substantial radiation dose should have followup at 10-14 days and at one month after the procedure for potential radiation
injuries.
4. Protection of staff during interventional fluoroscopy
The basic tools of occupational radiological protection are time, distance andshielding. The use of personal protective shielding is necessary in the cardiac
catheterization laboratory. Occupational doses can be reduced to very low levels if
ceiling suspended lead screens and protective lead curtains suspended from the sideof the procedure table are used properly. In general, reducing patient dose will also
reduce operator dose. With proper use of radiological protection tools andtechniques, the effective dose (E) for an interventionalist is typically 2–4 mSv/year,
and is well below the 20 mSv/year limit recommended by the Commission.
Radiation exposure to the operator is neither uniform nor symmetric.
Radiological protection for the eyes is necessary for interventionalists. Proper use of7

DRAFT REPORT FOR CONSULTATION
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307

personal monitoring badges is necessary in cardiac catheterization laboratories inorder to monitor and audit occupational radiation dose.
5. Radiological protection for nuclear cardiology
Appropriate use criteria and guidelines that help to set standards forjustification of nuclear cardiology procedures have been developed throughconsensus efforts of professional societies. Justification needs to be performed on
an individualized, patient-by-patient basis. Optimization of nuclear cardiology
procedures involves the judicious selection of radiopharmaceuticals andadministered activities to ensure diagnostic image quality while minimizing patient
dose. Administered activities should be within pre-specified ranges, as provided ininternational and national guidelines, and should reflect patient habitus. If stressimaging is normal, rest imaging can be omitted to minimize total dose. For SPECT
protocols, Tc-99m-based agents yield lower effective doses than Tl-201, and are
preferred on dosimetric grounds. Practitioners need good quality dosimetry data toperform proper benefit-risk analyses for their patients.
6. Radiological protection for cardiac CT
Appropriate use criteria and guidelines for justification of cardiac CT havebeen developed through consensus efforts of professional societies. Justificationneeds to be performed on an individualized, patient-by-patient basis, weighing thebenefits and risks of each imaging test under consideration as well as of doing notest. Assessment of radiation risk is one part of this process.
Dose from cardiac CT is strongly dependent on scanner mode, tube current,
and tube voltage. For patients with a heart rate less than 65-70 bpm and a regularrhythm, diagnostic image quality can generally be maintained while using dosereduction methods such as ECG-controlled tube current modulation and axial
imaging. The maximum tube current should be appropriate for the patient‘s habitus.
Further research is needed to develop and validate methods, such as newer scanmodes and low-voltage scanning, to minimize radiation dose to patients andpractitioners.
7. Radiological protection training for interventional fluoroscopy
Legislation in most countries requires that individuals who take responsibility
for medical exposures must be properly trained in radiological protection (RP).
Interventional cardiologists worldwide typically have little or no training in RP. The
Commission recommends that, in addition to the training recommended for otherphysicians who use X-rays, interventionalists, including interventional cardiologists,should receive a second, higher level of RP training.
Training programmes should include both initial training for all incoming staff
and regular updating and retraining. Scientific congresses should include refresher
courses on RP, attendance at which could be a requirement for continuing
professional development.
Training activities in RP should be followed by an evaluation of theknowledge acquired from the training programme (a formal examination system).
Physicians who have completed training should be able to demonstrate that they
8

DRAFT REPORT FOR CONSULTATION
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340

possess the knowledge specified by the curriculum by passing an appropriate
certifying examination.
The Commission recommends that nurses and other healthcare professionals
who assist during fluoroscopic procedures should be familiar with radiation risks
and radiological protection principles, in order to minimise their own exposure andthat of others.
8. Quality assurance programmes
Two basic objectives of the radiological protection quality assurance
programme (QAP) are to evaluate patient radiation dose on a periodic basis and tomonitor occupational radiation dose for workers in cardiology facilities whereradiation is used. A cardiologist should be in charge of the QAP aspects of RP for
cardiology procedures, and should be assisted by a medical physicist. A seniorinterventionalist and a medical physicist should be included in the planning for a
new interventional fluoroscopy laboratory, installation of a new x-ray or nuclear
medicine system and the upgrade of existing equipment.
Periodic evaluation of image quality and procedure protocols should be
included in the QAP. The QAP should establish a trigger level for individual clinicalfollow-up when there is a risk of radiation-induced skin injuries. The QAP should
ensure the regular use of personal dosimeters and include a review of all abnormal
dose values.
Patient dose reports should be produced at the end of procedures, archived andrecorded in the patient‘s medical record. If dose reports are not available, dosevalues should be recorded in the patient‘s medical record together with procedureand patient identification. Patient dose audits (including comparison with Diagnostic
Reference Levels) and reporting are important components of the QAP.
9. Reference
ICRP, 2007. The 2007 Recommendations of the International Commission on
Radiological Protection. ICRP publication 103. Ann. ICRP 37, 1-332.

9

DRAFT REPORT FOR CONSULTATION
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384

Recommendations


Individuals who request, perform or interpret cardiology imaging
procedures should be aware of the radiation risks of the procedure.
 Appropriate use criteria and guidelines for justification have beendeveloped and should be used in clinical practice.
 Nuclear cardiology examinations and cardiac CT examinations should be
optimized and dose reduction techniques used whenever applicable.
 The informed consent process should include information on radiation risk
if a risk of radiation injury is thought to exist.
 Radiation dose data should be recorded in the patient’s medical record
after the procedure; patient dose reports should be archived for quality
assurance purposes.
 When the patient’s radiation dose from an interventional procedure
exceeds the institution’s trigger level, clinical follow-up should be
performed for early detection and management of skin injuries.
 Suggested values for the trigger level are a skin dose of 3 Gy, a kerma-area
product of 500 Gy·cm2, or an air kerma at the patient entrance reference
point of 5 Gy.
 Individuals who perform cardiology procedures where there is a risk ofdeterministic injury to patients should be able to recognize these skin
injuries.
 Individuals who perform interventional cardiology procedures should befamiliar with methods to reduce radiation dose to patients and staff.
 Nurses and other healthcare professionals who assist during fluoroscopic
procedures should be familiar with radiation risks and radiologicalprotection principles, in order to minimise their own exposure and that ofothers.
 Whenever there is a possibility of occupational radiation exposure, staff
should use personal protective shielding.
 Training programmes in radiological protection should include both initialtraining for all incoming staff and regular updating and retraining.
 In addition to the training recommended for other physicians who use Xrays, interventionalists, including interventional cardiologists, should
receive a second, higher level of radiological protection training.
 A cardiologist should be in charge of the quality assurance programme
aspects of radiological protection for cardiology procedures, and should be
assisted by a medical physicist.
 Quality assurance programmes in cardiology should include patient dose
audits.
 Quality assurance programmes should ensure the regular use of personal
dosimeters and should include a review of all abnormal dose values.

10DRAFT REPORT FOR CONSULTATION
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431

GLOSSARY
1.

Definitions

Absorbed dose, D
The fundamental dose quantity given by

Where d is the mean energy imparted to matter of mass dm by ionisingradiation. The SI unit for absorbed dose is joule per kilogram (J kg-1). Its
special name is gray (Gy) (ICRP, 2007). In layman‘s terms, absorbed dose is
the measure of energy absorbed by tissue from ionizing radiation.
Acceptance test
A test carried out after new equipment has been installed or major
modifications have been made to existing equipment, in order to verify
compliance with the manufacturer‘s specifications, contractual specifications
and applicable local regulations.
ALARA
An acronym for As Low As Reasonably Achievable. See Optimisation ofprotection.
Becquerel (Bq)
The special name for the SI unit of activity. 1 Bq = 1 s-1 (≈2.7 10-11 Ci).
Brachytherapy
Radiation treatment of a patient using sealed or unsealed sources of radiation
placed within the patient‘s body.
Bradycardia
An abnormally slow heart rhythm. Depending on the heart rate and theunderlying abnormality, bradycardias may or may not require treatment.

Cardiomyopathy
Any condition that results in weakening of the pumping strength of the
cardiac ventricles, or that causes areas of scar tissue to develop in theventricles.
Cardiovertor-defibrillator
Devices, usually implanted in the same way as pacemakers, that
continuously monitor the heart rhythm, automatically function as pacemakers
11

DRAFT REPORT FOR CONSULTATION
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480

for bradycardia, and deliver life-saving shocks if a dangerous tachycardia is
detected.
Carers and comforters
Individuals, other than staff, who care for and comfort patients. These
individuals include parents and others, normally family or close friends, whohold children during diagnostic procedures or may come close to patients
following the administration of radiopharmaceuticals or during
brachytherapy (ICRP, 2007).
Commissioning
Testing carried out after new equipment has been installed, in order to verify
that the equipment is properly configured for its clinical application at thecentre (NCRP, 2010).
Constancy test
Each of a series of tests, carried out to ensure that the functional performanceof equipment meets established criteria, or to enable the early recognition ofchanges in the properties of components of the equipment (IEC, 1993).
Deterministic effectInjury in populations of cells, characterised by a threshold dose and anincrease in the severity of the reaction as the dose is increased further.
Deterministic effects are also termed tissue reactions. In some cases,
deterministic effects are modifiable by post-irradiation procedures including
biological response modifiers (ICRP, 2007).
Diagnostic reference level
Used in medical imaging with ionizing radiation to indicate whether, inroutine conditions, the patient dose or administered activity (amount ofradioactive material) from a specified procedure is unusually high or low forthat procedure (ICRP, 2007).
Diastasis
The midportion of diastole, when the blood enters the ventricle slowly orceases to enter. Diastasis duration is in inverse proportion to heart rate and isabsent at very high heart rates.
Dose coefficient
Used as a synonym for dose per unit intake of a radioactive substance, butsometimes also used to describe other coefficients linking quantities orconcentrations of activity to doses or dose rates, such as the external dose
rate at a specified distance above a surface with a deposit of a specified
activity per unit area of a specified radionuclide (ICRP, 2007).
Dose limit
The value of the effective dose or the equivalent dose to individuals fromplanned exposure situations that shall not be exceeded (ICRP, 2007).

12

DRAFT REPORT FOR CONSULTATION
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526

Dysrhythmia
A disorder of heart rhythm, also called arrhythmia. Dysrhythmias may be
due to electrical, circulatory or structural diseases or disorders. Somedysrhythmias are harmless, and some are life-threatening.
Effective dose, E
The tissue-weighted sum of the equivalent doses in all specified tissues andorgans of the body, given by the expression:

where HT or wRDT,R is the equivalent dose in a tissue or organ, T, and wT is
the tissue weighting factor. The unit for the effective dose is the same as forabsorbed dose, J kg-1. Its special name is sievert (Sv) (ICRP, 2007).
Effective dose was developed as a practical quantity for use in the generalsystem of radiation protection, particularly with regard to applying theprinciples of optimization of radiation protection and dose limitation forstochastic effects.
Electrophysiology
Cardiac electrophysiology is directed at evaluation and treating abnormalitiesof the electrical conduction system of the heart. Cardiac electrophysiology
procedures involve the recording of intracardiac electrical signals andprogrammed electrical stimulation of the heart. The procedure may be
performed for diagnostic purposes only or may be part of a combined
diagnostic and therapeutic (e.g., ablation) procedure. Catheters for pacing
and recording are advanced through blood vessels into multiple cardiac
chambers. The designs of the catheters and the sites appropriate for theirplacement are determined according to the nature of the arrhythmia underinvestigation.
EmployerAn organisation, corporation, partnership, firm, association, trust, estate,public or private institution, group, political or administrative entity, or otherpersons designated in accordance with national legislation, with recognizedresponsibility, commitment, and duties towards a worker in her or his
employment by virtue of a mutually agreed relationship. A self-employedperson is regarded as being both an employer and a worker (ICRP, 2007).
Equivalent dose, HT
The dose in a tissue or organ T given by:where DT,R is the mean absorbed dose from radiation R in a tissue or organT, and wR is the radiation weighting factor. Since wR is dimensionless, the13

DRAFT REPORT FOR CONSULTATION
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573

unit for the equivalent dose is the same as for absorbed dose, J kg-1. Thisunit‘s special name is sievert (Sv) (ICRP, 2007). For x-rays used influoroscopy, wR = 1, so the equivalent dose is numerically equal to the mean
absorbed dose in mGy.
Fluoroscopically guided interventions
Procedures comprising guided therapeutic and diagnostic interventions, bypercutaneous or other access, usually performed under local anaesthesia
and/or sedation, with fluoroscopic imaging used to localise thelesion/treatment site, monitor the procedure, and control and document thetherapy (ICRP, 2000).
Gray (Gy)The special name for the SI unit of absorbed dose: 1 Gy = 1 J kg-1.
Justification
The process of determining whether either (1) a planned activity involving
radiation is, overall, beneficial, i.e. whether the benefits to individuals and tosociety from introducing or continuing the activity outweigh the harm(including radiation detriment) resulting from the activity; or (2) a proposed
remedial action in an emergency or existing exposure situation is likely,
overall, to be beneficial, i.e., whether the benefits to individuals and tosociety (including the reduction in radiation detriment) from introducing or
continuing the remedial action outweigh its cost and any harm or damage it
causes (ICRP, 2007).
Interventional Reference Point, see Patient Entrance Reference Point
KAP, see Kerma-area productKerma, K
The quotient of the sum of the kinetic energies, dEtr, of all charged particles
liberated by uncharged particles in a mass dm of material, and the mass dmof that material.

Kerma is defined as a non-stochastic quantity and dEtr is the expectation
value of the sum of the kinetic energies. The unit for kerma is joule perkilogram (J kg-1). This unit‘s special name is gray (Gy) (ICRP, 2007).
―Kerma‖ is an acronym for Kinetic Energy Released in a Mass.
Kerma-area product, KAP
The integral of air kerma across the entire x-ray beam emitted from the x-ray
tube. Kerma-area product is a surrogate measurement for the entire amountof energy delivered to the patient by the beam. Kerma-area product ismeasured in units of Gy·cm2. This quantity was previously called dose-area

14

DRAFT REPORT FOR CONSULTATION
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616

product. Earlier publications used the abbreviation ‗DAP‘ for this quantity(Stecker et al, 2009).
Mean absorbed dose in a tissue or organ (T), DT
The absorbed dose DT, averaged over the tissue or organ T, which is given
bywhere εT is the mean total energy imparted in a tissue or organ T, and mT is
the mass of that tissue or organ (ICRP, 2007).
Medical exposure
Exposure incurred by patients as part of their own medical or dental
diagnosis or treatment; by persons, other than those occupationally exposed,
knowingly, while voluntarily helping in the support and comfort of patients;
and by volunteers in a programme of biomedical research involving their
exposure (ICRP, 2007).
Myocardial perfusion
Blood flow to the heart muscle.
Occupational exposureThis refers to all exposure incurred by workers in the course of their work,with the exception of 1) excluded exposures and exposures from exempt
activities involving radiation or exempt sources; 2) any medical exposure;and 3) the normal local natural background radiation (ICRP, 2007).
Optimisation of protection (and safety)
The process of determining what level of protection and safety makes
exposures, and the probability and magnitude of potential exposures, as low
as reasonably achievable, economic and societal factors being taken into
account (ICRP, 2007).
Patient Entrance Reference Point
For isocentric fluoroscopic systems such as C-arm fluoroscopes, the Patient
Entrance Reference Point is located along the central x-ray beam at a
distance of 15 cm from the isocenter in the direction of the focal spot (IEC,
2010). The earlier version of this standard refers to this point as theInterventional Reference Point. (IEC, 2000). The Patient Entrance Reference
Point is close to the patient‘s entrance skin surface when the heart is at theisocenter of the gantry.

15

DRAFT REPORT FOR CONSULTATION
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665

Peak Skin Dose, PSD
The maximum absorbed dose to the most heavily irradiated localized regionof skin (i.e., the localized region of skin that lies within the primary x-ray
beam for the longest period of time during an FGI procedure). Peak skindose is measured in units of Gy (NCRP, 168).
Percutaneous coronary intervention (PCI)
PCI encompasses a variety of procedures used to treat patients with diseased
coronary arteries. A catheter is advanced into the diseased artery, and aballoon is inflated within the stenotic portion of the artery, often
accompanied by placement of a stent (a wire mesh tube) to act as apermanent scaffold. The procedure is commonly known as coronary
angioplasty.
Principles of protection
A set of principles that apply equally to all controllable exposure situations:the principle of justification, the principle of optimisation of protection, andthe principle of application of limits on maximum doses in planned situations(ICRP, 2007).
PSD, see Peak Skin Dose
Radiation weighting factor, wR
A dimensionless factor by which the organ or tissue absorbed dose ismultiplied to reflect the higher biological effectiveness of high-LET
radiations compared with low-LET radiations. It is used to derive theequivalent dose from the absorbed dose averaged over a tissue or organ(ICRP, 2007).
Radiofrequency ablation
In cardiology, a procedure where one or more catheters are guided via
fluoroscopy into the blood vessels and directed to the heart muscle. A burstof radiofrequency energy destroys very small areas of tissue that give rise toabnormal electrical signals.
Reference Air Kerma (RAK)
Air kerma of the primary X-ray beam measured under specific conditions
and expressed as the equivalent value at the Patient Entrance Reference Point(IEC, 2004, IEC, 2010). It is the air kerma accumulated at a specific point inspace relative to the fluoroscopic gantry (see Patient Entrance Reference
Point, above) during a procedure. Reference air kerma does not include
backscatter and is measured in units of Gy. Reference air kerma is sometimes
referred to as reference dose or cumulative air kerma. Earlier publications
used the term ‗cumulative dose‘ and the abbreviation ‗CD‘ for this quantity(Stecker, 2009).
Sievert (Sv)
The special name for the SI unit of equivalent dose, effective dose, andoperational dose quantities. The unit is joule per kilogram (J kg-1).
16

DRAFT REPORT FOR CONSULTATION
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713

SRDL, see Substantial Radiation Dose Level
Stochastic effects of radiation
Malignant disease and heritable effects for which the probability of an effectoccurring, but not its severity, is regarded as a function of dose without
threshold (ICRP, 2007).
Stenosis
Narrowing of a hollow structure. With respect to percutaneous coronary
interventions, narrowing of the inner diameter of a coronary artery.
Stress test
A standardized procedure for assessing the effect of stress on heart function
and myocardial perfusion. Stress may be induced by exercise or simulated byadministration of drugs. A normal stress test implies that blood flow throughthe coronary arteries is normal.
Substantial Radiation Dose Level (SRDL)
An appropriately selected reference value used to trigger additional dosemanagement actions during a procedure and medical follow-up for aradiation level that might produce a clinically relevant injury in an averagepatient. There is no implication that radiation levels above the SRDL will
always cause an injury or that radiation levels below the SRDL will nevercause an injury (NCRP 168, 2010).
Tachycardia
An abnormally fast heart rhythm. Depending on the heart rate and theunderlying abnormality, tachycardias may or may not require treatment.
Threshold dose for tissue reactions
Dose estimated to result in only 1% incidence of tissue reactions (ICRP,
2007).
Tissue reaction
See ‗Deterministic effect‘.
Tissue weighting factor, wT
The factor by which the equivalent dose in a tissue or organ T is weighted torepresent the relative contribution of that tissue or organ to the total healthdetriment resulting from uniform irradiation of the body (ICRP 1991). It isweighted such that:(ICRP, 2007).
Valvular heart disease17

DRAFT REPORT FOR CONSULTATION
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750

Heart disease due to one or more abnormal heart valves. Abnormallynarrowed or leaky heart valves can interfere with the heart‘s ability to pushblood forward from chamber to chamber, and then out to the lungs and body.
WorkerAny person who is employed, whether full time, part time or temporarily, by
an employer, and who has recognised rights and duties in relation to
occupational radiological protection (ICRP, 2007).
2.

References

IEC, 1993. Medical electrical equipment - Part 1-61223: Evaluation and routine
testing in medical imaging departments. 1st ed. Geneva, Switzerland:International Electrotechnical Commission.
IEC, 2000. Medical electrical equipment. Part 2-43: Particular requirements for thesafety of X-ray equipment for interventional procedures. IEC 60601-2-43.
Geneva, Switzerland: International Electrotechnical Commission.
IEC, 2004. Medical electrical equipment - Technical Report 60788: Glossary ofdefined terms. IEC TR 60788. 2nd edition. Geneva, Switzerland: International
Electrotechnical Commission.
IEC, 2010. Medical electrical equipment. Part 2-43: Particular requirements for thesafety of X-ray equipment for interventional procedures. IEC 60601-2-43. 2ndedition. Geneva, Switzerland: International Electrotechnical Commission.
ICRP, 1991. The 1990 Recommendations of the International Commission on
Radiological Protection. ICRP Publication 60. Ann ICRP 21(1-3):1-201.
ICRP, 2000. Avoidance of radiation injuries from medical interventional
procedures. ICRP Publication 85. Ann ICRP 30:7-67.
ICRP, 2007. The 2007 Recommendations of the International Commission on
Radiological Protection. ICRP Publication 103. Ann ICRP 37(2-4):1-332.
NCRP, 2010. Radiation dose management for fluoroscopically guided
interventional medical procedures. NCRP Report No. 168. Bethesda, MD:
National Council on Radiation Protection and Measurements.
Stecker MS, Balter S, Towbin RB, Miller DL, Vañó E, Bartal G, Angle JF, Chao
CP, Cohen AM, Dixon RG, Gross K, Hartnell GG, Schueler B, Statler JD, deBaère T, and Cardella JF. Guidelines for patient radiation dose management. J
Vasc Interv Radiol 2009; 20: S263-S273.

18

DRAFT REPORT FOR CONSULTATION
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799

1. INTRODUCTION
Main Points








In cardiology, patient radiation exposure is due to nuclear medicine, CT,
percutaneous coronary interventions, electrophysiology procedures,procedures for the correction of congenital heart disease or acquired
valvular disease, and other vascular interventional procedures.
Cardiac nuclear medicine, CT, percutaneous coronary interventions andelectrophysiology procedures are increasing in number and account for adisproportionate share of patient radiation exposure.
Interventional cardiology procedures can result in patient skin doses highenough to cause radiation injury and an increased risk of cancer inchildren.
Complexpercutaneous
coronary
interventions
andcardiacelectrophysiology procedures are associated with higher radiation doses
Treatment of congenital heart disease in children is of particular concern,due to their greater sensitivity to radiation.
Staff in cardiac catheterization laboratories may receive high radiation
doses if radiological protection tools are not used properly.
1.0 Introduction(1)
In cardiology, patients are exposed to ionizing radiation from threedifferent modalities: fluoroscopy (including cineangiography), computed
tomography (CT) and nuclear medicine. These three modalities differ considerably
in the frequency with which they are performed, in patient radiation doses, in theway radiation is administered to the patient, and in radiation dose to operators andstaff.
1.1 Fluoroscopically guided procedures(2)
Cardiologists perform a variety of fluoroscopically guided procedures.
These include procedures to diagnose and treat abnormal coronary arteries,
procedures to diagnose and treat cardiac dysrhythmias, procedures to diagnose andtreat congenital and valvular heart disease and other vascular interventions. These
procedures may be performed on patients of all ages, from newborns to the elderly.
The Commission has addressed avoidance of radiation injury from fluoroscopicallyguided procedures in the past (ICRP 2000), but advances in technology and in our
understanding of radiation effects have occurred in the past decade.
1.1.1 Percutaneous coronary interventions (PCI)(3)
Despite the continuing development of non-invasive cardiac imaging
techniques over the past decade, including echocardiography, cardiac CT scanningand cardiac MRI, an increasing number of patients undergo fluoroscopically guided
19

DRAFT REPORT FOR CONSULTATION
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820

invasive cardiac diagnostic and therapeutic procedures. In Europe there was a 3-foldincrease in coronary angiography (CA) and a 5-fold increase in percutaneous
coronary interventions (PCI) between 1992 and 2001, primarily due to theintroduction of coronary stents (Togni, et al, 2004, fig. 1.1) Between 1990 and 2003,
the average annual rate of increase in coronary angioplasty procedures in Europe
ranged from 3.78% in the Netherlands to 11.82% in Finland, with a mean of 6.73%(Faulkner and Werduch, 2008a). An estimated 3,043,000 coronary arteriograms and910,000 percutaneous coronary interventions, with 690,000 coronary stentplacements, were performed in Europe in 2007 (Faulkner and Werduch, 2008b).
(4)
Similar growth rates were observed in North America (Laskey et al, 2000,
Anderson et al, 2002) for the time period 1990-2000. Between 2006 and 2008,
however, the number of invasive coronary procedures in the U.S. declined byapproximately 2% (NCRP Report 168, 2010), and appears to be declining in some
European countries as well (Meier, 2010). This is presumed due to the increase in
cardiac CT.
(5)
In the United States, interventional fluoroscopy procedures were the thirdlargest source of medical exposure of patients in 2006, accounting for 14% of
medical exposure (NCRP report 160, 2009). Cardiac procedures were 28% of thetotal interventional fluoroscopy procedures, but accounted for 53% of theinterventional fluoroscopy exposure.

821
822
823
824
825
826

Figure 1.1: Coronary angiograms, coronary angioplasty (PTCA) andcoronary stenting in Europe from 1992—2001, in thousands of procedures(from Togni, EHJ reproduced with permission [to be requested from ElsevierLtd.])

827

20

DRAFT REPORT FOR CONSULTATION
828
829
830
831
832
833
834
835
836
837
838
839
840
841

(6)
This growth has involved mainly the Western world, but a similar trend isseen in other countries: in China the annual increment rate for PCI is around 40%(Cheng et al, 2004). This number is relatively small and may reflect the lower
prevalence of coronary artery disease in the Chinese population (3-7%, about one
quarter of that of Western Caucasians), but is expected to grow as a consequence ofchanging dietary habits, life-style and cigarette smoking (Cheng et al, 2004, Moran
2010).
(7)
A survey of developing countries conducted by the IAEA revealed thatabout 30% of the 20 participating countries demonstrated a 100% increase inworkload in the 3-year period from 2004 to 2007 (Tsapaki, 2009). The same study
indicated that the numbers of paediatric interventional procedures can reach thelevels of adult interventional procedures, even in developing countries.

842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867

(8)
Both PCI and interventional electrophysiology procedures can result inpatient skin doses high enough to cause deterministic skin injuries (see Chapters 2
and 3) (Miller 2008). At one centre, the frequency of skin injuries was estimated at
3 x 10-4 (Padovani 2005). Although the number of radiation injuries due to cardiac
procedures remains small, these injuries have a major impact on the patients who are
affected. Therefore, it is important to inform and continue to remind practicing
clinicians of the potential risks involved with these procedures.
(9)
The number of patients undergoing multiple procedures continues toincrease (Laskey et al, 2001). Complex cases may be treated in more than one
session (staged procedures). Restenosis and disease progression may also prompt
repeated interventions. In a recent series of 3332 patients (Padovani et al, 2005)
almost one third underwent at least two procedures. Vano et al. (Vano 2001)
observed a much greater rate of skin effects in patients who had undergone multiple
fluoroscopically guided coronary procedures. Repeated procedures, especially when
performed within a short period of time, increase the risk of skin injury (Balter,2010). Multiple cardiac fluoroscopic procedures should be a cause of concern withregard to radiological protection. The risk of skin injuries should not be
underestimated.
(10) Patient radiation dose is related to procedure complexity (Bernardi et al,
2000, Peterzol et al, 2002, Balter et al, 2009, IAEA 2009). Multi-vessel PCI isconsidered a complexity factor, but this may not be always the case (Bernardi et al,2000). Other factors that appear to affect complexity for PCI include the type oflesion, the chronicity of the occlusion, the degree of vessel tortuosity and the
involvement of vessel bifurcations (Balter et al, 2009, IAEA 2009).

868
869
870
871
872
873
874
875

(11) A second field where there has been an increase in both the number andcomplexity of procedures is interventional electrophysiology. Permanent pacemaker
implantation for bradycardia is carried out in large numbers of patients. From 1997
to 2001, the number of new pacemaker implants increased about 50% worldwide(Mond et al, 2004).
More recently, bi-ventricular pacemakers (cardiac
resynchronisation therapy) have been introduced for the treatment of patients withcardiac failure and cardiomyopathies (Salukhe et al, 2004). The use of cardioverterdefibrillators has also increased, as a result of studies (Moss et al, 2002, Salukhe et1.1.2 Skin injuries

1.1.3 Cardiac electrophysiology procedures

21

DRAFT REPORT FOR CONSULTATION
876
877
878
879
880
881
882
883
884
885
886
887
888
889

al, 2004) that demonstrated their life-saving role in patients at risk of sudden cardiac
death. An estimated 554,000 pacemaker implantations were performed in Europe in2007 (Faulkner and Werduch, 2008b) and an estimated 189,000 electrophysiology
procedures and 361,000 cardiac device implantations were performed in the U.S. in2008 (NCRP Report No. 168, 2010).
(12) Cardiac electrophysiology procedures also include treatment of patientswith re-entrant tachycardias. These patients are often much younger than patientswith coronary heart disease, and require both diagnostic procedures and treatment byradiofrequency ablation. Due to the long fluoroscopy times required for theseprocedures, these patients can be exposed to very high radiation doses and asubstantial risk of deterministic effects if technique is not optimized (Rosenthal,
1998, McFadden, 2002).

890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919

(13) Two other groups of cardiac disease where catheter techniques are used
and are likely to expand in the near future are congenital and valvular heart disease.
These groups represent a small percentage of patients undergoing percutaneousinterventions, but these diseases are seen in both children and adults. Children are at
greater risk for the development of stochastic radiation effects, principally cancer,
due to their longer expected life span and their increased sensitivity to radiation ascompared to adults (Hall, 2009). It has been estimated that approximately 7% of all
cardiac angiography procedures are carried out in children aged 0 to 15 years(UNSCEAR 2000).
The most widely performed procedures are balloon
valvuloplasty, device closure of atrial septal defect, patent foramen ovale or ductus
arteriosus, stenting of pulmonary artery stenosis or coarctation of the aorta andelectrophysiology studies. These procedures may involve long fluoroscopy times. In
addition to these well-established procedures, new procedures have been introduced,
including percutaneous pulmonary and aortic valve replacement, ventricular septal
defect closure, implantation of banding devices to limit pulmonary blood flow, andradiofrequency perforation to create continuity between cardiac chambers andvessels (Levi et al, 2003). (Percutaneous aortic valve replacement is performed
primarily in elderly patients unfit for surgery). A percutaneous or combined
percutaneous/surgical approach has been proposed to treat complex diseases such as
hypoplastic left heart syndrome. Fetal interventions are also possible.
(14) These techniques to treat congenital and valvular heart disease are largely
justified as they may replace very high-risk surgical procedures. Althoughtransesophageal and intracardiac ultrasound may partially replace fluoroscopy (Riceet al, 2002, Zanchetta et al, 2004), radiation risk still remains a problem and is often
underestimated. Fluoroscopy times as high as 129 minutes may be required to
implant a pulmonary valve (Bonhoeffer et al, 2002). There is little literature
concerning the safety issues of these new devices to be used in infants and children(Levi et al, 2003).

920
921
922
923

(15) A survey of patient doses in 137 children, aged from < 1 year to 16 years,
undergoing cardiac procedures performed using a biplane flat panel detector X-ray
system, demonstrated mean values of 1.9 to 8.6 Gy·cm2 for diagnostic procedures.
Mean dose values for therapeutic procedures, in both extremes of the paediatric age

1.1.4 Congenital and valvular heart disease

1.1.5 Paediatric patients22

DRAFT REPORT FOR CONSULTATION
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972

group, ranged from 2.4 to 17.8 Gy·cm2 (Martinez et al, 2007). In a series of 205
children (mean age 4.1 y) who underwent diagnostic cardiac catheterization, themean dose was 17 Gy·cm2 (Chida et al, 2010). In comparison to proposed diagnostic
reference levels for fluoroscopically guided cardiac interventions in adults of 50
Gy·cm2 for diagnostic procedures and 125 Gy·cm2 for therapeutic procedures(Balter et al, 2008), paediatric patients have typically received less than 20% of thedose received by adult patients. Nonetheless, radiation doses from paediatric cardiac
catheterization procedures are of concern (Andreassi, 2006, Andreassi, 2009).
1.2

Cardiac CT(16) Cardiac CT technology has evolved rapidly in recent years, and theseadvancements have enabled a variety of types of cardiac CT studies to be performedthat go well beyond detection of the coronary arteries. Today, cardiac CT
encompasses several distinct procedures, including coronary artery calcium (CAC)
scoring, CT coronary angiography (CTCA), pulmonary vein CT angiography, andCT attenuation correction of nuclear cardiology image data. Recent technologicaladvances have been associated with an increase in the number of procedures
performed, although reliable statistics on worldwide numbers are not presently
available. In the United States, CT was the largest source of medical exposures topatients in 2006, accounting for 49% of the medical exposure of patients (NCRP
report 160, 2009). Cardiac CT (including CTCA and CAC) accounted for 4.7% of
CT examinations, but 12.1% of patient exposure from CT.
1.3

Nuclear cardiology(17) An estimated 32.7 million diagnostic nuclear medicine procedures are
performed annually worldwide (UNSCEAR 2008). Of these, approximately 14
million are nuclear cardiology procedures, and this number has increased rapidly(Davis, 2006). More than 90% of nuclear cardiology studies are myocardial
perfusion scintigraphy studies for the assessment of myocardial perfusion and/or
viability. The vast majority of nuclear cardiology procedures performed employ
single photon emission computed tomography (SPECT), although a small but
growing number of laboratories perform positron emission tomography (PET)studies.
(18) In the U.S., nuclear medicine procedures accounted for 26% of the
medical exposure of patients in 2006, and cardiac studies accounted for 85% of thenuclear medicine exposure (NCRP report 160, 2009). Nuclear medicine procedures
were the second largest source of medical exposures, after CT.
(19) More nuclear cardiology procedures are performed in the United States
than in the rest of the world combined. Reasons suggested for this disparity include
better access to testing, a more litigious medicolegal climate, and profit motives fortesting. However, multiple U.S. series have demonstrated that for those procedures
where sufficient data are available to permit a determination of appropriateness, only
~15% are performed for inappropriate indications (Gibbons, 2008; Hendel, 2010).
Nonetheless, cardiologists should consider using alternative methodologies that do
not require ionizing radiation, such as stress echocardiography, whenever possible.

23

DRAFT REPORT FOR CONSULTATION
973

1.4

Occupational radiation risk

974
975
976
977
978
979
980
981
982
983
984
985
986

(20) Radiation risk is not limited to patients. Operators and staff receive
radiation exposure during fluoroscopically guided procedures. The increased
complexity of interventional cardiology procedures appears to have offset dose
reductions due to improvements in technology (Kim, 2008). There is considerable
variation in operator doses observed for the same type of procedure, indicating thatradiological protection practices can be improved (Kim, 2009). Recent studies haveshown that there is an increased incidence of radiation-related cataracts ininterventional cardiologists when radiological protection tools are not used properly(Vano, 2010, Ciraj-Bjelac, 2010) Unfortunately, there is lack of proper monitoringof radiation doses to staff and lack of reliable data on occupational doses (Padovani,2011).

987
988
989
990
991
992
993
994
995
996
997

(21) In summary, fluoroscopically guided cardiology procedures are increasing
in number and complexity. The benefits for patients are clear, but radiation doses forboth patients and staff are important and must be managed appropriately. For young
patients, the increased risk of cancer should be considered in the optimisation ofthese procedures. For older patients cancer risk is not as important, but avoidance ofdeterministic effects (skin injuries) should be taken into account. Interventional
cardiologists are among the radiation workers with the highest occupationalradiation risk, and should know how to protect both patients and themselves. This
ICRP report is intended to help achieve this goal.

998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020

Anderson HV, Shaw RE, Brindis RG, Hewitt K, Krone RJ, Block PC, McKay CR,
Weintraub WS. A contemporary overview of percutaneous coronary
interventions. The American College of Cardiology-National Cardiovascular
Data Registry (ACC-NCDR). J Am Coll Cardiol 2002; 39:1096-103.
Andreassi MG, Ait-Ali L, Botto N, Manfredi S, Mottola G, Picano E. Cardiac
catheterization and long-term chromosomal damage in children with congenital
heart disease. Eur Heart J 2006; 27:2703–2708.
Andreassi MG. Radiation risk from pediatric cardiac catheterization: friendly fireon children with congenital heart disease. Circulation 2009;120(19):1847-1849.
Balter S, Miller DL, Vano E, Ortiz Lopez P, Bernardi G, Cotelo E, Faulkner K,
Nowotny R, Padovani R, Ramirez A. A pilot study exploring the possibility of
establishing guidance levels in x-ray directed interventional procedures. Med
Phys 2008;35:673-80.
Balter S, Hopewell JW, Miller DL, Wagner LK, Zelefsky MJ. Fluoroscopicallyguided interventional procedures: A review of radiation effects on patients' skinand hair. Radiology 2010;254:326-341.
Bernardi G, Padovani R, Morocutti G, Vano E, Malisan MR, Rinuncini M,
Spedicato L, Fioretti PM. Clinical and technical determinants of the complexityof PTCA procedures. Analysis in relation to radiation exposure parameters.
Cathet Cardiovasc Interv 2000;51:1-9.
Bonhoeffer P, Boudjemline Y, Qureshi SA, Le Bidois J, Iserin L, Acar P, Merckx J,
Kachaner J, Sidi D. Percutaneous insertion of the pulmonary valve. J Am Coll
Cardiol 2002;39:1664-9.

1.5

1.6

Summary

References

24

DRAFT REPORT FOR CONSULTATION
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068

Ciraj-Bjelac O, Rehani MM, Sim KH, Liew HB, Vano E, Kleiman NJ. Risk forradiation induced cataract for staff in interventional cardiology: Is there reason
for concern? Catheter Cardiovasc Interv 2010;76(6):826-834.
Cheng TO. The current state of cardiology in China. Int J Cardiol. 2004
Sep;96(3):425-39.
Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, Takahashi S,
Zuguchi M. Radiation dose to the pediatric cardiac catheterization andintervention patient.
AJR American Journal of Roentgenology 2010;
195(5):1175-1179.
Davis W. Mapping improvements in molecular imaging. Medical Imaging.
2006;May
2006.
Availableat:
http://www.imagingeconomics.com/issues/articles/MI_2006-05_01.asp
Accessed December 31, 2010.
Fajadet J, Morice MC, Bode C, Barragan P, Serruys PW, Wijns W, Constantini CR,
Guermonprez JL, Eltchaninoff H, Blanchard D, Bartorelli A, Laarman GJ, Perin
M, Sousa JE, Schuler G, Molnar F, Guagliumi G, Colombo A, Ban Hayashi E,
Wulfert E. Maintenance of long-term clinical benefit with sirolimus-eluting
coronary stents: three-year results of the RAVEL trial. Circulation
2005;111:1040-4.
Faulkner K, Werduch A. An estimate of the collective dose to the European
population from cardiac x-ray procedures. Br J Radiol 2008a; 81:955-962.
Faulkner K, Werduch A. Analysis of the frequency of interventional cardiology invarious European countries. Rad Prot Dosim 2008b; 129(1-3):74-76.
Hall EJ. Radiation biology for pediatric radiologists. Pediatr Radiol 2009;39 Suppl
1:S57-64.
Gibbons RJ, Miller TD, Hodge D, et al. Application of appropriateness criteria tostress single-photon emission computed tomography sestamibi studies andstress echocardiograms in an academic medical center. J Am Coll Cardiol.
2008;51(13):1283-1289.International Atomic Energy Agency. Establishingguidance levels in x ray guided medical interventional procedures: A pilot
study. Safety Reports Series No. 59. Vienna: International Atomic Energy
Agency; 2009.
Hendel RC, Cerqueira M, Douglas PS, et al. A multicenter assessment of the use of
single-photon emission computed tomography myocardial perfusion imaging
with appropriateness criteria. J Am Coll Cardiol. 2010;55(2):156-162.
International Commission on Radiological Protection. Avoidance of radiation
injuries from medical interventional procedures. ICRP Publication 85. Ann
ICRP 2000;30:7-67.
Kim KP, Miller DL, Balter S, Kleinerman RA, Linet MS, Kwon D, Simon SL.
Occupational radiation doses to operators performing cardiac catheterization
procedures. Health Phys 2008;94:211-227.
Kim KP, Miller DL. Minimising radiation exposure to physicians performing
fluoroscopically guided cardiac catheterisation procedures: a review. Radiat
Prot Dosimetry 2009;133:227-33.
Laskey WK, Kimmel S, MD, Krone RJ. Contemporary Trends in Coronary
Intervention: A Report From the Registry of the Society for Cardiac
Angiography and Interventions Cathet. Cardiovasc. Intervent. 49:19–22, 2000.

25

DRAFT REPORT FOR CONSULTATION
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116

Laskey WK, Williams DO, Vlachos HA, MS, H, Holmes DR, King SB, Kelsey SF,
Slater J, Faxon D, Al-Bassam M, Block E, Detre KM for the Dynamic Registry
Investigators. Changes in the Practice of Percutaneous Coronary Intervention: A
Comparison of Enrollment Waves in the National Heart, Lung, and Blood
Institute (NHLBI) Dynamic Registry. Am J Cardiol 2001;87:964–969.
Lemos PA, Serruys PW, van Domburg RT, Saia F, Arampatzis CA, Hoye A,
Degertekin M, Tanabe K, Daemen J, Liu TK, McFadden E, Sianos G, Hofma
SH, Smits PC, van der Giessen WJ, de Feyter PJ. Unrestricted utilization ofsirolimus-eluting stents compared with conventional bare stent implantation in
the "real world": the Rapamycin-Eluting Stent Evaluated At Rotterdam
Cardiology Hospital (RESEARCH) registry. Circulation 2004;109:190-5.
Levi DS, Alejos JC, Moore JW. Future of interventional cardiology in pediatrics.
Curr Opin Cardiol. 2003;18:79-90.
Martinez LC, Vano E, Gutierrez F, Rodriguez C, Gilarranz R, Manzanas MJ.
Patient doses from fluoroscopically guided cardiac procedures in pediatrics.
Phys Med Biol. 2007;52(16):4749-59.
McFadden SL, Mooney RB, Shepherd PH. X-ray dose and associated risks fromradiofrequency catheter ablation procedures. Br J Radiol 2002;75:253-65.
Meier, B. Cardiac catheterization interventions: European statistics 2007/2008.
Presented
at
Euro
PCR,
May,
2010.
Availableat:
http://www.escardio.org/communities/EAPCI/Documents/Cardiaccatheterization-Interventions-stats07-08-EAPCI-Assembly-may2010.pdf
Accessed February 22, 2011.
Miller DL. Overview of contemporary interventional fluoroscopy procedures.
Health Phys 2008;95:638-44.
Mond HG, Irwin M, Morillo C, Ector H. The world survey of cardiac pacing andcardioverter defibrillators: calendar year 2001. Pacing Clin Electrophysiol
2004;27:955-64
Moran A, Gu D, Zhao D, Coxson P, Wang YC, Chen CS, Liu J, Cheng J, BibbinsDomingo K, Shen YM, He J, Goldman L. Future cardiovascular disease inchina: markov model and risk factor scenario projections from the coronary
heart disease policy model-china. Circ Cardiovasc Qual Outcomes.
2010;3(3):243-52.
Morice MC, Serruys PW, Sousa JE, Fajadet J, Ban Hayashi E, Perin M, Colombo
A, Schuler G, Barragan P, Guagliumi G, Molnar F, Falotico R; RAVEL Study
Group. Randomized Study with the Sirolimus-Coated Bx Velocity BalloonExpandable Stent in the Treatment of Patients with de Novo Native Coronary
Artery Lesions. A randomized comparison of a sirolimus-eluting stent with astandard stent for coronary revascularization. N Engl J Med 2002;346:1773-80.
Moss AJ, Zareba W, Hall WJ, Klein H, Wilber DJ, Cannom DS, Daubert JP,
Higgins SL, Brown MW, Andrews ML; Multicenter Automatic Defibrillator
Implantation Trial II Investigators. Prophylactic implantation of a defibrillator
in patients with myocardial infarction and reduced ejection fraction. N Engl J
Med 2002;346:877-83.
National Council on Radiation Protection and Measurements. Ionizing radiation
exposure of the population of the United States. NCRP Report No. 160.
Bethesda, MD: National Council on Radiation Protection and Measurements;
2009.

26

DRAFT REPORT FOR CONSULTATION
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164

National Council on Radiation Protection and Measurements. Radiation dosemanagement for fluoroscopically guided interventional medical procedures.
NCRP Report No. 168. Bethesda, MD: National Council on Radiation
Protection and Measurements; 2010.
Padovani R, Bernardi G, Quai E, Toh HS, Signor M, Morocutti G, Spedicato L.
Retrospective evaluation of occurrence of skin injuries in interventional cardiac
procedures. Radiat Prot Dosimetry 2005; 117 (1-3):247-250.
Padovani, R., Le Heron, J., Cruz-Suarez, R., Duran, A., Lefaure, C., Miller, D.L.,
Sim, H.K., Vano, E., Rehani, M., Czarwinski, R., 2010. International project on
individual monitoring and radiation exposure levels in interventional
cardiology. Radiat Prot Dosimetry 2011; in press.
Peterzol A, Quai E, Padovani R, Bernardi G, Kotre J, Dowling A. Reference levels
in PTCA as a function of procedure complexity. Radiat Prot Dosimetry
2005;117 (1-3): 54-58.
Prieto C, Vano E, Fernández JM, Galvan C, Sabate M, Gonzalez L, Martinez D. Six
years experience in intracoronary brachytherapy procedures: patient doses fromfluoroscopy. Br J Radiol. 2006 Sep; 79(945): 730-733.
Rice MJ, McDonald RW, Li X, Shen I, Ungerleider RM, Sahn DJ. New
Technology and Methodologies for Intraoperative, Perioperative, andIntraprocedural Monitoring of Surgical and Catheter Interventions forCongenital Heart Disease Echocardiography 2002; 19:725-734.
Rosenthal LS, Mahesh M, Beck TJ, Saul JP, Miller JM, Kay N, Klein LS, Huang S,
Gillette P, Prystowsky E, Carlson M, Berger RD, Lawrence JH, Yong P,
Calkins H. Predictors of fluoroscopy time and estimated radiation exposure
during radiofrequency catheter ablation procedures. Am J Cardiol 1998;82:451458.
Salukhe TV, Dimopoulos K, Francis D. Cardiac resynchronisation may reduce allcause mortality: meta-analysis of preliminary COMPANION data with
CONTAK-CD, InSync ICD, MIRACLE and MUSTIC. Int J Cardiol
2004;93:101-3.
The SoS Investigators. Coronary artery bypass surgery versus percutaneous
coronary intervention with stent implantation in patients with multivessel
coronary artery disease (the Stent or Surgery trial): a randomized controlled
trial. Lancet 2002;360:965–70.
Togni M, Balmer F, Pfiffner D, Maier W, Zeiher AM, Meier B, on behalf of theWorking Group Interventional Cardiology and Coronary Pathophysiology of theEuropean Society of Cardiology. Percutaneous coronary interventions in Europe
1992–2001. Eur Heart J 2004;25:1208–1213.
Tsapaki, V., Ahmed, N.A., AlSuwaidi, J.S., Beganovic, A., Benider, A.,
BenOmrane, L., Borisova, R., Economides, S., El-Nachef, L., Faj, D.,
Hovhannesyan, A., Kharita, M.H., Khelassi-Toutaoui, N., Manatrakul, N.,
Mirsaidov, I., Shaaban, M., Ursulean, I., Wambani, J.S., Zaman, A., Ziliukas, J.,
Zontar, D., Rehani, M.M., 2009. Radiation exposure to patients during
interventional procedures in 20 countries: initial IAEA project results. AJR.
Am. J. Roentgenol. 193, 559-569.
UNSCEAR. Sources and effects of ionizing radiation: volume I, sources: annex D,
medical radiation exposure. Report to the General Assembly of the United
Nations;
2000;
New
York,
NY
Available
at:27

DRAFT REPORT FOR CONSULTATION
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193

http://www.unscear.org/unscear/en/publications/2000_1.html
Accessed
December 31, 2010.
UNSCEAR. Sources of ionizing radiation: volume I. Report to the General
Assembly, with scientific annexes; 2010; New York, NY. Available at:
http://www.unscear.org/unscear/en/publications/2008_1.html
Accessed
December 31, 2010.
Vano E, Goicolea J, Galvan C, Gonzalez L, Meiggs L, Ten JI, Macaya C. Skinradiation injuries in patients following repeated coronary angioplasty
procedures. Br J Radiol. 2001 Nov;74(887):1023-31.
Vano E, Kleiman NJ, Duran A, Rehani MM, Echeverri D, Cabrera. M. Radiation
cataract risk in interventional cardiology personnel. Radiat Res, 2010;
174(4):490-495
Verin V, Popowski Y, de Bruyne B, Baumgart D, Sauerwein W, Lins M, Kovacs G,
Thomas M, Calman F, Disco C, Serruys PW, Wijns W, Piessens M, Kurtz J,
Simon R, Delafontaine P, Erbel R. Endoluminal Beta-Radiation Therapy for thePrevention of Coronary Restenosis after Balloon Angioplasty. N Engl J Med
2001;344:243-249.
Waksman R, Bhargava B, White L, Chan RC, Mehran R, Lansky AJ, Mintz GS,
Satler LF, Pichard AD, Leon MB, Kent KK. Intracoronary beta-radiation
therapy inhibits recurrence of in-stent restenosis. Circulation 2000;101:1895-8.
Williams DO, Holubkov R, Yeh W, Bourassa MG, Al-Bassam M, Block PC, CoadyP, Cohen H, Cowley M, Dorros G, Faxon D, Holmes DR, Jacobs A, Kelsey SF,
King SB, Myler R, Slater J, Stanek V, Vlachos HA, Detre KM. PercutaneousCoronary Intervention in the Current Era Compared With 1985–1986 The
National Heart, Lung, and Blood Institute Registries. Circulation
2000;102:2945-2951.
Zanchetta M, Maiolino P. Intracardiac echocardiography. Do we need a new
ultrasonographic window? Ital Heart J 2004;5:173-177.

28

DRAFT REPORT FOR CONSULTATION
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241

2. THE BIOLOGICAL EFFECTS OF RADIATION
Main Points









Deterministic effects are due to injury in populations of cells,
characterised by a threshold dose and an increase in the incidence andseverity of the reaction as the dose is increased further. Deterministic
effects are also termed tissue reactions.
Stochastic effects are malignant disease and heritable effects for which
the probability of an effect occurring, but not its severity, is regarded asa function of dose without threshold.
Radiation-induced skin injuries may not become fully manifest untilmonths after the radiation dose was administered.
The diagnosis of a radiation induced skin injury is often delayed.
The lens of the eye is a radiosensitive tissue.
In the lens of the eye, ionizing radiation typically causes posterior
subcapsular cataract formation.
Surveys of cardiologists and support staff working in catheterizationlaboratories have found a high percentage of lens opacities attributableto occupational radiation exposure when radiological protection tools
have not been used properly.
2.1

Types of radiation effects(22) The effects of radiation can be classified into two groups: deterministic
effects (harmful tissue reactions) and stochastic effects (cancer and heritableeffects).
(23) Deterministic effects (e.g. skin injury) are largely caused by the
reproductive sterilisation of cells following high radiation doses. The induction oftissue reactions is generally characterised by a threshold dose. The reason for thepresence of this threshold dose is that radiation-induced reproductive survival of a
critical population of cells in a given tissue needs to be sustained before injury isexpressed in a clinically relevant form. Above the threshold dose the incidence andseverity of the injury, including impairment of the capacity for tissue recovery,
increases with dose (ICRP 103). The threshold is variable, depending on the natureand condition of the exposed tissue (Balter, 2010).
(24) The injury is not expressed clinically until the cells die as a result of an
unsuccessfully attempt at cell division or differentiation and are lost as part of thenormal process of tissue turnover (Balter, 2010). The incidence as well as theseverity of the injury, including impairment of the capacity for tissue recovery,
increases with dose. After a high radiation dose, the outcome for the affectedindividual can be devastating (Balter, 2010).
(25) Eighty percent of reported radiation-induced skin injuries in one large
series were from cardiac procedures (Koenig et al 2001). Nonetheless, cardiologists
often do not recognise that a radiation injury is related to a cardiac procedure, either
because they are unaware of the magnitude of radiation dose delivered or they do
not know that radiation can cause skin injuries.
29

DRAFT REPORT FOR CONSULTATION
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290

(26) The dose of radiation received by some patients is high and the number ofradiation injury cases is increasing (NCI, 2005). However, most currently practisinginterventional cardiologists have no personal experience of a case of radiation
injury. The number of radiation injuries is small compared with the number offluoroscopically guided cardiology procedures performed worldwide.
(27) Stochastic effects The accumulation of cellular and animal data relevant toradiation tumourigenesis has, since 1990, strengthened the view that DNA damage
response processes in single cells are of critical importance to the development ofcancer after radiation exposure. Epidemiological and experimental studies provide
evidence of radiation risk, albeit with uncertainties at doses about 100 mSv or less
(ICRP 103).
(28) These effects are probabilistic—there is no identifiable threshold for
producing the effect. The likelihood of inducing a stochastic effect increases with
dose, but the exact relationship between dose and effect is not known. In the lowdose range, below about 100 mSv, it is scientifically plausible to assume that theincidence of cancer or heritable effects will rise in direct proportion to an increase in
the equivalent dose in the relevant organs and tissues (the ―linear-non-threshold‖ or
LNT model) (ICRP 103). Dose has no relationship to the severity of the effect.
(29) Children are approximately 2-3 times more sensitive to the stochastic
effects of radiation than adults (ICRP 1991). They also have a longer potential
lifespan than do adults, so they have more time to develop possible radiation relatedsequelae. In children, the probability of a fatal cancer per fluoroscopically guided
procedure is estimated at approximately 0.07-0.08%, but this risk may vary widely
depending on patient age, underlying life expectancy and how the procedure is
performed (Martinez et al, 2007, Bacher et al, 2005).
(30) While there is compelling evidence that radiation causes heritable effects
in experimental animals, there continues to be no direct evidence that exposure ofhumans to radiation leads to excess heritable disease in offspring (ICRP 103).
2.2

Background(31) Some months after the discovery of x-rays in 1895, radiation-induced skinchanges were observed (Daniel 1896, Codman 1896). Some early radiologists
suffered severe dermatitis, radiation cancer and amputation of digits. There was adelay in recognising that x-rays were the cause because they are invisible and do notcause any sensation during exposure. As noted in ICRP Publication 103, the goal of
preventing these radiation injuries was the impetus for the formation of what is now
the Commission (ICRP 2007).
(32) Following the dramatic rise in the number of percutaneous coronary
interventional procedures, cases of patients with deep skin ulceration and necrosis
were reported in the 1990s (Shope, 1996). In 1994 the U.S. Food and Drug
Administration issued an advisory regarding skin injury from fluoroscopicallyguided procedures (FDA 1994). Radiation skin injury has also been reported
following radiofrequency catheter ablations (Vano, 1998). This is of particularconcern because many of these patients are young adults, and some are children.
The Commission drew attention to prevention of skin injuries from interventional
fluoroscopy procedures in Publication 85 (ICRP 2000), and reiterated theimportance of preventing skin injuries in Publication 105 (ICRP 2007).

30

DRAFT REPORT FOR CONSULTATION
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331

2.3

Radiation Effects and the Skin

(33) The response of the skin to radiation is dose-related and occurs when thisdose is concentrated on one area, usually the site where the x-rays enter the patient.
The term ―absorbed dose‖ is used to assess the amount of radiation to which a tissue
is exposed (see the Glossary). The skin response follows a characteristic pattern,although the time course is variable (Balter et al, 2010). The threshold doses andtime of appearance for various types of skin injury are summarised in Table 2.1.
(34) Defects in DNA repair genes may predispose individuals to radiogenic
cancer or lower the threshold for the development of deterministic effects. Somepatients with serious and unanticipated radiation injuries may be among the 1% of
the population heterozygous for the ATM gene, an autosomal recessive gene
responsible for ataxia telangiectasia, or may harbour some other ATM abnormality.
(Hymes, 2006, Allan, 2008) Other disorders with a genetic component affecting
DNA breakage or repair also increase radiation sensitivity, including Fanconi
anaemia, Bloom syndrome and xeroderma pigmentosum. Familial polyposis,
Gardner syndrome, hereditary malignant melanoma and dysplastic nevus syndrome
also increase radiation sensitivity (Hymes, 2006). Certain familial cancer syndromes
may increase susceptibility to radiogenic cancer, including neurofibromatosis, LiFraumeni syndrome and hereditary retinoblastoma (Allan, 2008).
(35) Autoimmune and connective tissue disorders predispose patients to thedevelopment of severe cutaneous radiation effects in an unpredictable fashion.
These typically occur in association with the high radiation doses administeredduring radiation therapy. The aetiology is not known. These disorders include
scleroderma, systemic lupus erythematosus and possibly rheumatoid arthritis.((Wagner et al, 1999, Hymes, 2006) Hyperthyroidism and diabetes mellitus are also
associated with increased radiation sensitivity (Koenig Part 1, 2001) Diabetes isbelieved to predispose to radiation injury secondary to small vessel vascular diseaseand consequent decreased healing capacity (Herold, 1999). A number of drugs
increase radiation sensitivity, including actinomycin D, doxorubicin, bleomycin, 5fluorouracil and methotrexate (Koenig Part 1, 2001) Again, this effect is usuallyseen only with the high radiation doses delivered during radiation therapy.
(36) It is apparent from the foregoing and from Table 2.1 that there are no
rigid thresholds for dose or time of appearance of radiation-induced skin changes,
because individuals vary in their radio-sensitivity and radio-responsiveness (Balter
et al, 2010). These ranges are shown graphically in Figure 2.1. In the discussion
below, threshold doses are given for an average person, but it should be understoodthat these will vary from individual to individual. For most patients, clinicallyimportant skin reactions occur only when the absorbed skin dose is greater than
5 Gy (Balter et al, 2010; ICRP Tissue Reactions, 2011a).

31

DRAFT REPORT FOR CONSULTATION
1332
1333

Table 2.1: Tissue reactions from a single-delivery radiation dose to the skin of the neck, torso, pelvis, buttocks orarms. (from Balter et al, 2010)- This table is applicable to the normal range of patient radiosensitivities in the absence of mitigating or aggravating physical or clinical factors.
- Skin dose refers to absorbed skin dose (including backscatter). This quantity is not the reference air kerma (Ka,r) described by the Food andDrug Administration (21 CFR § 1020.32 (2008)) or the International Electrotechnical Commission.(IEC, 2010)- This table does not apply to the skin of the scalp.
- Abrasion or infection of the irradiated area is likely to exacerbate radiation effects.
- The dose and time bands are not rigid boundaries. Signs and symptoms are expected to appear earlier as the skin dose increases.
Single-site
Acute SkinBand
Dose Range
1
(Gy)
A1
0-2
A2
2-5

B

5-10

NCI
Skin
Reaction
Grade*N/A
1

Approximate time of onset of effects(4) Prompt< 2 weeks- Epilation- Transient erythema- Erythema, epilation

1

D

10-15

> 15

1-2

3-4

Mid term
6 – 52 weeks

No observable effects expected- Recovery from hair loss

- Transient erythema- Transient erythemaC(5) Early
2 – 8 weeks- Recovery.
- At higher doses;
prolonged erythema,
permanent partial
epilation- Erythema, epilation.
(9) Prolonged- Possible dry or moist erythema.
desquamation- Permanent epilation.
(8)
Recoveryfrom desquamation- Transient erythema- Erythema, epilation. (12) - Dermal atrophy,- After very high doses,(11) Moist - Secondary ulceration due
edema and acutedesquamation
to failure of moist
ulceration; long-term
desquamation to heal;
surgical intervention likely tosurgical intervention likely
be required.
to be required.
- At higher doses, dermal
necrosis; surgicalintervention likely to berequired..

Long term> 40 weeks

(6)
(7)

- None expected- Recovery.
- At higher doses dermal
atrophy/induration.

(10)

2

(13)

2

- Telangiectasia- Dermal atrophy/induration.
- Skin likely to be weak.

- Telangiectasia .
- Dermal atrophy/induration,- Possible late skin breakdown.
- Wound might be persistent andprogress into a deeper lesion.
- Surgical intervention likely to berequired.

1

Skin dosimetry is unlikely to be more accurate than ± 50%
Refers to radiation-induced telangiectasia. Telangiectasia associated with an area of initial moist desquamation or the healing ofulceration may be present earlier.
*NCI = U.S. National Cancer Institute232

DRAFT REPORT FOR CONSULTATION
1334
1335

1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358

Figure 2.1: Graphical representation of data in Table 2.1 showing overlap in the skineffects with both dose and time.

(37) The lowest dose that may produce a noticeable skin change in individuals withaverage radiation sensitivity is conventionally considered to be 2 Gy. Histamine-like
substances are activated and dilate capillaries, resulting in reddening (transient erythema).
This usually occurs within hours of exposure and fades after 24 hours. This effect islikely to be under-reported due to its short duration.
(38) After a dose of 6 Gy, a second hyperaemic phase (main erythema) commences
at approximately 10 days. This phase may be apparent earlier after doses > 6 Gy. It
results from the destruction of proliferating basal cells in the epidermis. The patient may
complain of burning, tenderness and itching, and the skin becomes warm andoedematous. The erythema usually peaks at 2 weeks and fades by 4 weeks (Koenig et al,2001).
(39) If doses exceed 10 Gy, the erythema may be more prolonged, withhyperpigmentation. At skin doses > 14 Gy the inflammation can progress to dry
desquamation—the erythematous skin is covered with scales and flakes of corneum, with
an appearance resembling sunburn. Moist desquamation occurs at doses of about 18 Gy.
The skin blisters and sloughs with weeping of serum from the deep cutaneous layers.
33

DRAFT REPORT FOR CONSULTATION
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402

This is associated with considerable pain and the skin becomes susceptible to infection.
Topical antibiotics are often required (Shack et al, 1987). The proliferative cells in thebasal layer of the epidermis are damaged and reduced in number. Desquamation usuallyappears 4 weeks after exposure and can last many weeks, particularly if secondary
infection occurs.
(40) A late phase of erythema can develop 8-10 weeks after radiation exposure of
approximately 15 Gy. The skin has a mauve or dusky appearance. A skin dose of about
18 Gy may result in vascular insufficiency of the dermis, leading to ischemic dermal
necrosis 10-16 weeks following exposure. The damage is greater at higher doses (Koenig
et al, 2001).
(41) Dermal atrophy occurs after prolonged erythema, particularly when associatedwith moist desquamation. This is typically seen in two phases, initially at 3 months andthen at 1 year. At doses above 10 Gy, telangiectasia may also develop because of dilationof the dermal capillaries. This is often a late phenomenon, occurring more than a year
after exposure, but has been noted earlier and can increase over time (Turreson et al,1986). Trauma may precipitate late necrosis in skin that shows these late changes. The
threshold for this is approximately12 Gy, so it may be seen in the absence of earlier skindesquamation.
(42) The diagnosis of a radiation-induced skin injury is often delayed because theselesions are relatively rare and the cause may not be recognized. Also, there is often alatent period of many months before the lesion is fully apparent (Balter et al, 2010).
Patients often seek care from a dermatologist, rather than the physician who performed
the interventional procedure. As a result, the history of fluoroscopy may be overlooked
or considered irrelevant (Frazier et al 2007). Skin biopsy is frequently performed,
although the results are not specific for radiation injury and can lead to a non-healing
ulcer, as can other forms of trauma. Misdiagnoses are often made, including contact
dermatitis from an electrode pad, allergy to adhesive tape or skin disinfectant, drug
eruption, viral or bacterial infection and even insect bite. The deep pain associated withan injury may lead to extensive chest and abdominal evaluation (Vlietstra et al 2004).
Severe injuries may extend into muscle (Monaco et al, 2003).
(43) Skin cancer directly related to radiation from an interventional procedure has
not been reported. Cases of basal cell carcinoma have been documented following x-ray
treatment for scalp ringworm (Shore 2002) with a relative risk of 3.6 after a scalp dose of
4.8 Gy. The relative risk of skin cancer in Chinese medical x-ray workers has been
estimated at 4.1 in a cohort studied from 1950 – 1995. (Wang 2002)
2.4

The Lens of the Eye and Radiation(44) The prevalence of cataract is difficult to estimate, as it depends in part on thedefinition of cataract. The Framingham Eye Study (Kahn et al, 1977) found a 91%
prevalence in 75-85 year olds, although this figure was reduced to 46% if ‗modest visual
deficit‘ is added to the definition. A more recent Spanish study gave a prevalence of
cataract and decreased visual acuity of more than 60% of 75 year olds. (Acosta et al,
2006)

34

DRAFT REPORT FOR CONSULTATION
1403
1404
1405
1406
1407
1408
1409

(45) The majority of lens opacities that are not due to radiation are associated withcortical changes in the superficial substance of the lens. The lens is a radiosensitive
tissue. Ionizing radiation typically causes posterior subcapsular (PSC) cataract formation(Figure 2.2). Unlike an age-related cataract, which usually interferes initially with visualacuity, a PSC cataract reduces contrast sensitivity before reducing visual acuity.

1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446

Figure 2.2: a) A radiation-induced posterior subcapsular (PSC) cataract is shown as acentral black shadow at the posterior aspect of the lens. b) Retroillumination photographof a PSC cataract at the posterior aspect of the lens. This causes glare and poor vision inbright light conditions as well as poor reading vision. (From RSNA News, June 2004
(http://www.rsna.org/Publications/rsnanews/upload/jun2004.pdf)) [Permission to berequested from RSNA](46) The response of the lens to radiation has traditionally been considered adeterministic effect. The threshold dose for detectable human lens opacities has been
considered to be 2 Sv for a single acute exposure and 5 Sv for protracted exposure. For
cataract with visual impairment, the thresholds have been considered to be 5 Sv and 8 Sv
respectively. (ICRP 1991, NCRP 1993). More recent data in populations exposed tolower doses of radiation suggest that dose related lens opacification occurs at exposuressignificantly lower than 2 Sv, and that there may be no dose threshold. (Worgul et al,
2007, Kleiman 2007, NCRP 168, 2010, Shore 2010, ICRP XXX [Tissue Reactions],
2011a)(47) There have been reports of radiation-induced cataracts in interventionalists
who have performed procedures for a number of years, and of doses to the lensapproaching the annual limit of 150 mSv during angiographic procedures (Figure 2.3)

35

DRAFT REPORT FOR CONSULTATION
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473

1474
1475
1476
1477

(Vano et al, 1998, Pages 2000, Hidajat 2006, Vano et al 2010). Recent studies haveshown that with typical reported interventional workloads the radiation dose to the lens
may exceed the current threshold for deterministic effects after several years of work, if
radiological protection tools are not used (Vano et al, 2008, Kim et al, 2008) Several
surveys of cardiologists and support staff working in catheterization laboratories,
conducted with coordination provided by the International Atomic Energy Agency(IAEA) in Latin America and Asia, have found a high percentage of lens opacities
attributable to occupational radiation exposure (Vano et al, 2010, Ciraj-Bjelac et al,2010).
(48) These recent data and the mechanistic uncertainties regarding cataract
development have highlighted the need for a detailed reappraisal of the radiosensitivity of
the lens of the eye. This issue is addressed in ICRP Publication XXX, on Tissue
Reactions and Other Non-Cancer Effects of Radiation and its Statement on Tissue
Reactions (ICRP, 2011a, 2011b). The previous Commission recommendation (ICRP,
1991) of a dose limit of 150 mSv per year for occupational exposure in a planned
exposure situation (e.g., occupational exposure of interventionalists) has been changed.
The Commission now recommends that the lens dose limit for chronic occupational
exposure should be 20 mSv in a year, averaged over defined periods of 5 years, with nosingle year exceeding 50 mSv, i.e. the same as the annual whole body limit for workers(ICRP, 2011a, 2011b).
(49) The Commission now considers the threshold in absorbed dose to the lens of
the eye to be 0.5 Gy (ICRP, 2011b). The Commission judges, based on existing
evidence, that an acute dose of up to around 100 mGy produces no functional impairmentof tissues, including the lens of the eye with respect to cataract, although the use of athreshold model remains uncertain for this tissue (ICRP, 2011a).

Figure 2.3: PSC cataract in the eye of an interventionist using an old x-ray system andhigh scatter radiation from improper working conditions (E. Vano BJR 1998)
36

DRAFT REPORT FOR CONSULTATION
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521

2.5

Cardiovascular effects of radiation exposure(50) The mechanisms of heart radiation damage include inflammatory processes, inparticular after low doses, and after higher doses there is a progressive reduction in thenumber of patent capillaries eventually leading to ischemia, myocardial cell death andfibrosis, accelerated atherosclerosis in major blood vessels, decreased cardiac function,and fatal congestive heart failure. There are no known mitigators of radiation-induced
cardiovascular disease (ICRP, 2011).
(51) Analyses of the atomic bomb survivors have shown that radiation doses above
0.5 Gy are associated with an elevated risk of both stroke and heart disease (Shimizu etal, 2010). These findings are consistent with other studies that demonstrated an increased
risk of heart disease after radiation therapy to the chest (Bhatti et al, 2008). There iscompelling evidence that ionizing radiation in the doses using for radiation therapy canincrease the risk of heart disease (McGale and Darby, 2008).
(52) Radiation induced heart disease can occur as a result of both microvasculardamage to the myocardium, leading to focal myocardial degeneration and fibrosis, andaccelerated atherosclerosis in major blood vessels. Cardiovascular radiation effects havebeen reported to occur at doses > 0.5 Gy (ICRP, 2011). Although uncertainty remains,
medical practitioners should be aware that the absorbed dose threshold for circulatory
disease may be as low as 0.5 Gy to the heart (ICRP, 2011b). In some complex
fluoroscopically guided cardiac procedures, organ doses may be > 0.5 Gy. Theseradiation effects need to be considered during the optimization process.
(53) At lower doses (below 0.5 Gy) the relationship between radiation dose andincreased cardiovascular risk is unclear (Shimizu et al, 2010). McGeoghegan andcolleagues (2008) observed an association between mortality from non-cancer causes ofdeath, particularly circulatory system disease, and exposure to ionizing radiation in theiranalysis of 42,000 radiation workers with low-dose, long-term radiation exposure. Other
studies have shown mixed results (McGale and Darby, 2008). Recent reviews of
epidemiological studies of populations medically, occupationally or environmentally
exposed to relatively low-dose radiation showed that there was substantial heterogeneity
in the association between radiation exposure and circulatory disease, with respect to therisk per unit radiation dose, possibly resulting from confounding factors or bias (ICRP,
2011). As there is no clear understanding of the underlying biological mechanisms, it isdifficult to interpret these mixed results (Dauer et al, 2010).
2.6

Occupational radiation exposure and intracranial neoplasms(54) Ionizing radiation is one of the few established causes of neural tumours(Yonehara et al., 2004). Preston and colleagues studied the incidence of nervous system
tumours in atomic bomb survivors (Preston et al., 2007; Preston et al., 2002). They founda significant dose-related excess of nervous system tumours. They concluded that
exposure to doses of radiation as low as < 1 Sv is associated with an elevated incidence

37

DRAFT REPORT FOR CONSULTATION
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564

of nervous system tumours (Preston et al., 2002). It is clear that in children, radiation
exposure is associated with the development of brain cancer, but the relationship in
individuals exposed as adults is much less clear. The association between benign
intracranial tumours and radiation appears to be substantially stronger than for malignant
tumours (UNSCEAR, 2000). However, the BEIR-VII report does not explicitly present
Lifetime Attributable Risk (LAR) for brain cancer incidence or mortality (NRC, 2006).
What is clear is that for operators and staff, the brain is one of the least protected organs
during interventional fluoroscopy procedures.
(55) Radiation dose to the brain in fluoroscopists has not been well studied. Wenzl
noted that cardiologists may receive the highest radiation doses of any specialists who
use fluoroscopy for interventional procedures (Wenzl, 2005). Renaud determined thatthe annual exposure to cardiologists‘ heads was approximately 20 – 30 mSv (Renaud,1992). However, Renaud‘s study was performed with data from 1984 through 1988,
when both cardiac interventions and fluoroscopic equipment were less sophisticated thanthey are now.
(56) Finkelstein suggested that the occurrence of brain tumours in two Toronto
cardiologists in a one-year period might indicate that they were radiation-induced(Finkelstein, 1998). Epidemiologic evidence for radiation-induced brain cancer influoroscopists is suggestive, but by no means conclusive. In 1975, Matanoski andcolleagues found that the death rate from brain cancer in American radiologists wasalmost 3 times that of other medical specialists who did not use radiation (Matanoski etal., 1975). In a Swedish case-control study of 233 patients with brain tumours, Hardelland colleagues reported that work as a physician using fluoroscopy increased the risk ofdeveloping a brain tumour, with an odds ratio of 6.0 (95% confidence interval, 0.6257.7), but there were only 3 such individuals among the 233 cases (Hardell et al., 2001).
No increased risk was found for other health care workers. In a case-control study of 476
individuals diagnosed with gliomas between 1991 and 1994 in the San Francisco area,
Carozza and colleagues observed an increased risk in physicians and surgeons (odds ratio
3.5, 95% confidence interval 0.7-17.6) (Carozza et al., 2000). There were only 6
physicians in the group, and the authors suggested that the increased risk might be due tooccupational exposure to numerous biologic agents and chemicals as well as to radiation.
On the other hand, Blettner and colleagues conducted a case-control study in Germany of
844 patients with brain tumours and 1737 control subjects, using self-reported medical
and occupational data (Blettner et al., 2007). More than 2/3 of the 91 participants
occupationally exposed to radiation were in the medical field (physicians, nurses,
radiographers). Blettner and colleagues found no significant risk of brain tumours as aresult of exposure to medical ionizing radiation. Karipidis and colleagues conducted acase-control study in Australia of 416 patients with gliomas and 422 controls and foundno evidence of an association between gliomas and ionizing radiation (Karipidis et al.
2007).
2.7

References

38

DRAFT REPORT FOR CONSULTATION
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608

Acosta R, Hoffmeister L, Roman R, Comas M, Castilla M, Castells X. Systematic
review of population-based studies of the prevalence of cataracts. Arch Soc Esp
Oftalmol 2006; 81: 509-516
Allan JM. Genetic susceptibility to radiogenic cancer in humans. Health Phys 2008;
95:677-686.
Bacher K, Bogaert E, Lapere R, De Wolf D, Thierens H. Patient-specific dose andradiation risk estimation in pediatric cardiac catheterization. Circulation. 2005 Jan
4;111(1):83-9.
Balter S, Hopewell JW, Miller DL, Wagner LK, Zelefsky MJ. Fluoroscopically guided
interventional procedures: A review of radiation effects on patients' skin and hair.
Radiology 2010; 254:326-41.
Bhatti P, Sigurdson AJ, Mabuchi K.
Cam low-dose radiation increase risk ofcardiovascular disease? Lancet 2008; 372:697-699.
Blettner M., Schlehofer B., Samkange-Zeeb F., Berg G., Schlaefer K., Schüz J. (2007)
Medical exposure to ionising radiation and the risk of brain tumours: Interphonestudy group, Germany. Eur J Cancer 43:1990-8.
Carozza S.E., Wrensch M., Miike R., Newman B., Olshan A.F., Savitz D.A., Yost M.,
Lee M. (2000) Occupation and adult gliomas. Am J Epidemiol 152:838-46.
Finkelstein M.M. (1998) Is brain cancer an occupational disease of cardiologists? Can J
Cardiol 14:1385-8.
Ciraj-Bjelac O, Rehani MM, Sim KH, Liew HB, Vano E, Kleiman NJ. Risk for radiationinduced cataract for staff in interventional cardiology: Is there reason for concern?
Catheter Cardiovasc Interv 2010;76(6):826-834.
Codman EA. The cause of burns from x-rays. (letter) Bos Med Surg J 1896; 136:610611
Daniel J. The x-rays. (letter) Science 1896; 3:562
Dauer LT, Brooks AL, Hoel DG, Morgan WF, Stram D, Tran P. Review and evaluationof updated research on the health effects associated with low-dose ionising radiation.
Radiat Prot Dosim 2010; 140(2):103-136
Frazier TH, Richardson JB, Fabre VC, Callen JP. Fluoroscopy-induced chronic
radiation skin injury: a disease perhaps often overlooked. Arch Dermatol 2007;
143(5): 637-640
Hardell L., Hansson Mild K., Påhlson A., Hallquist A. (2001) Ionizing radiation, cellular
telephones and the risk for brain tumours. Eur J Cancer Prev 10:523-9.
Herold DM, Hanlon AL, Hanks GE. Diabetes mellitus: a predictor for late radiation
morbidity. Int J Radiat Oncol Biol Phys 1999; 43: 475-479
Hidajat N, Wust P, Felix R, Schroder RJ. Radiation exposure to patient and staff in
hepatic chemoembolization: risk estimation of cancer and deterministic effects.
Cardiovasc Intervent Radiol 2006; 29(5): 791-796
Hymes SR, Strom EA, Fife C. Radiation dermatitis: clinical presentation,
pathophysiology, and treatment 2006. J Am Acad Dermatol 2006;54:28-46
IEC. Report 60601 Medical electrical equipment - Part 2-43: Particular requirements forthe safety of X-ray equipment for interventional procedures. 2nd ed. Geneva,
Switzerland: International Electrotechnical Commission; 2010.

39

DRAFT REPORT FOR CONSULTATION
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651

ICRP, 1990. The 1990 Recommendations of the International Commission on
Radiological Protection. ICRP Publication 60. Ann ICRP 1991; 21(1-3):1-201
ICRP, 2000. Avoidance of radiation injuries from medical interventional procedures.
ICRP Publication 85. Ann ICRP 30:7-67.
ICRP, 2007a. The 2007 Recommendations of the International Commission on
Radiological Protection. ICRP Publication 103. Ann ICRP 37(2-4):1-332
ICRP, 2007b.. Radiological protection in medicine. ICRP Publication 105. Ann ICRP
37:1-63
ICRP Protection 2011a. Tissue Reactions and Other Non-Cancer Effects of Radiation.
ICRP Publication XXX. Ann ICRP 2011; in press
ICRP 2011b. Statement on Tissue reactions. Approved by the Commission on April
21,
2011.
Availableat
http://www.icrp.org/docs/ICRP%20Statement%20on%20Tissue%20Reactions.pdf
Accessed May 9, 2011. (in press)
Kahn, HA, Liebowitz HM, Ganley JP, Kini MM, Colton T, Nickerson RS, Dawber TR.
The Framingham Eye Study. I. Outline and major prevalence findings. Am J
Epidemiol 1977; 106(1): 17-32
Karipidis KK, Benke G, Sim MR, Kauppinen T, Giles G. (2007) Occupational exposure
to ionizing and non-ionizing radiation and the risk of glioma. Occup Med (Lond)
57:518-524.
Kim KP, Miller DL, Balter S, Kleinerman RA, Linet MS, Kwon D, Simon SL.
Occupational radiation doses to operators performing cardiac catheterization
procedures. Health Phys 2008;94:211-227.
Kleiman NJ. Radiation cataract. In: Working Party on Research Implications on Healthand Safety Standards of the Article 31 Group of Experts, ed. Radiation Protection
145 EU Scientific Seminar 2006 New insights in radiation risk and basic safety
standards. Brussels: European Commission; 2007:81-95.
Available at
http://ec.europa.eu/energy/nuclear/radioprotection/publication/doc/145_en.pdf
Accessed July 28, 2010
Koenig TR, Wolff D, Mettler FA, Wagner LK. Skin injuries from fluoroscopicallyguided procedures: Part 1, Characteristics of radiation injury. AJR 2001; 177: 3-11
Martinez LC, Vano E, Gutierrez F, Rodriguez C, Gilarranz R, Manzanas MJ. Patient
doses from fluoroscopically guided cardiac procedures in pediatrics. Phys Med Biol
2007; 52: 4749-4759.
Matanoski G.M., Seltser R., Sartwell P.E., Diamond E.L., Elliott E.A. (1975) The
current mortality rates of radiologists and other physician specialists: specific causesof death. Am J Epidemiol 101:199-210.
McGale P, Darby SC. Commentary: A dose-response relationship for radiation-induced
heart disease—current issues and future prospects. Int J Epidemiol 2008; 37:518523
McGeoghegan D, Binks K, Gillies M, Jones S, Whaley S. The non-cancer mortality
experience of male workers at British Nuclear Fuels plc, 1946-2005. Int J Epidemiol
2008; 37:506-518

40

DRAFT REPORT FOR CONSULTATION
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694

Monaco JL, Bowen K, Tadros PN, Witt PD. Iatrogenic deep musculocutaneous radiation
injury following percutaneous coronary intervention. J Invasive Cardiol
2003;15:451-3.
National Cancer Institute, 2005. Interventional fluoroscopy: reducing radiation risks forpatients and staff. NIH Publication No. 05-5286. National Cancer Institute,
Bethesda, MD. Available at: http://www.cancer.gov/images/Documents/45bae965697a-4de8-9dae-b77222e0e79d/InterventionalFluor.pdf Accessed December 31,
2010.
National Council on Radiation Protection and Measurements. Limitation of exposure toionizing radiation. NCRP Report 116. Bethesda, MD: National Council on Radiation
Protection and Measurements; 1993.
National Council on Radiation Protection and Measurements. Radiation dosemanagement for fluoroscopically guided interventional medical procedures. NCRP
Report No. 168. Bethesda, MD: National Council on Radiation Protection andMeasurements; 2010.
NRC. (2006) Health risks from exposure to low levels of ionizing radiation: BEIR-VII
Phase 2 National Academy Press, Washington, DC.
Pages J. Effective dose and dose to the crystalline lens during angiographic procedures.
JBR-BTR 2000; 83:108-110
Preston D.L., Ron E., Tokuoka S., Funamoto S., Nishi N., Soda M., Mabuchi K.,
Kodama K. (2007) Solid cancer incidence in atomic bomb survivors: 1958-1998.
Radiat Res 168:1-64.
Preston D.L., Ron E., Yonehara S., Kobuke T., Fujii H., Kishikawa M., Tokunaga M.,
Tokuoka S., Mabuchi K. (2002) Tumors of the nervous system and pituitary glandassociated with atomic bomb radiation exposure. J Natl Cancer Inst 94:1555-63.
Renaud L. (1992) A 5-y follow-up of the radiation exposure to in-room personnel during
cardiac catheterization. Health Phys 62:10-15.
Shack RB, Lynch JB. Radiation dermatitis. Clin Plast Surg 1987; 14: 391-401
Shimizu Y, Kodama K, Nishi N, Kasagi F, Suyama A, Soda M, Grant EJ, Sugiyama H,
Sakata R, Moriwaki H, Hayashi M, Konda M, Shore RE. Radiation exposure andcirculatory disease risk: Hiroshima and Nagaski atomic bomb survivor data, 19502003. BMJ 2010; 340:b5349
Shope, T.B., 1996. Radiation-induced skin injuries from fluoroscopy. Radiographics 16,1195-1199.
Shore RE, Moseson M, Xue X, Tse Y, Harley N, Pasternack BS. Skin cancer after x-ray
treatment for scalp ringworm. Radiat Res 2002: 157 (4): 410-418
Shore, R.E., Neriishi, K., Nakashima, E., 2010. Epidemiological studies of cataract risk
at low to moderate radiation doses: (not) seeing is believing. Radiat. Res. 174, 889894.
Turreson I, Notter G. The predictive value of skin telangiectasia for late radiation effectin different normal tissues. Int J Radiat Oncol Biol Phys 1986; 12 603-609
UNSCEAR. (2000) Sources and effects of ionizing radiation. United Nations, New
York.

41

DRAFT REPORT FOR CONSULTATION
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733

United States Food and Drug Administration . Public Health Advisory. Avoidance ofserious x-ray induced skin injuries to patients during fluoroscopically guided
procedures. Rockville, MD: Center for Devices and Radiological Health, UnitedStates
Food
and
Drug
Administration,
1994
Availableat
http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotificati
ons/ucm063084.htm Accessed July 29, 2010.
Vano E, Arranz L, Sastre JM, Moro C, Ledo A, Garate MT, Minguez I. Dosimetric andradiation protection considerations based on some cases of patient skin injuries ininterventional cardiology. Br J Radiol 1998; 71: 510-516
Vano E, Gonzalez L, Beneytez F, Moreno F. Lens injuries induced by occupational
exposure to non-optimized interventional radiology laboratories. Br J Radiol 1998;
71: 728-733
Vano E, Gonzalez L, Fernandez M, Haskal ZJ. Eye lens exposure to radiation ininterventional suites: caution is warranted. Radiology 2008; 248: 945-953
Vano E, Kleiman NJ, Duran A, Rehani MM, Echeverri D, Cabrera. M. Radiation
cataract risk in interventional cardiology personnel. Radiat Res, 2010; 174(4):490495
Vlietstra RE, Wagner LK, Koenig T, Mettler F. Radiation burns as a severe complicationof fluoroscopically guided cardiological interventions. J Int Cardiol 2004; 17(3): 112
Wagner LK, McNesse MD, Marx MV, Siegel EL. Severe skin reactions frominterventional fluoroscopy: case report and review of literature. Radiology 1999;
213: 773-776
Wang JX, Zhang LA, Li BX, Zhao YC, Wang ZQ, Zhang JY, Aoyama T. Cancer
incidence and risk estimation among medical x-ray workers in China, 1950-1955.
Health Phys 2002; 82(4): 455-466
Wenzl T.B. (2005) Increased brain cancer risk in physicians with high radiation
exposure. Radiology 235:709-10; author reply 710-1.
Worgul BV, Kundiyev YI, Sergiyenko NM, Chumak VV, Vitte PM, Medvedovsky C,
Bakhanova EV, Junk AK, Kryrychenko OY, Musijachenko NV, Shylo SA, Vitte OP,
Xu S, Xue X, Shore RE. Cataracts among Chernobyl clean-up workers: implications
regarding permissible eye exposures. Radiat Res 2007; 167(2): 233-243
Yonehara S., Brenner A.V., Kishikawa M., Inskip P.D., Preston D.L., Ron E., Mabuchi
K., Tokuoka S. (2004) Clinical and epidemiologic characteristics of first primarytumors of the central nervous system and related organs among atomic bomb
survivors in Hiroshima and Nagasaki, 1958-1995. Cancer 101:1644-54.

42

DRAFT REPORT FOR CONSULTATION
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777

3. CLINICAL EXAMPLES OF DETERMINISTIC INJURY AFTERFLUOROSCOPICALLY GUIDED CARDIAC PROCEDURES
Main PointsThere is increasing concern about skin radiation dose levels in cardiology.
The cases presented in this chapter provide a clinical context and illustrateskin changes due to radiation injury.
Deterministic injuries may extend into deeper tissues and can cause symptoms
that persist for years.
Deterministic injuries may be accompanied by an increase in stochastic risk.
3.1

Introduction(57) There is increasing concern about skin radiation dose levels in cardiology.
This is because of the discovery of deterministic injuries in patients who have undergone
long procedures using suboptimal equipment, performed by individuals inadequately
trained in radiological protection (UNSCEAR, 2010). However, high skin doses canoccur in obese patients, or patients undergoing complex interventions, even when theprocedure is performed by an experienced, well-trained operator using modern, wellmaintained equipment (Suzuki, 2008; Bryk, 2006).
(58) The information presented in Chapter 2 (section 2.3) on the radiobiology of theskin can be difficult to interpret without a clinical context. The cases presented in thischapter provide that clinical context and illustrate the skin changes discussed in Chapter
2. It should be apparent that these injuries can be severe and debilitating. Some patients
will require life-long therapy and observation.
Treatment often requires amultidisciplinary team working in a specialized centre. Pain management andpsychological support are important components of treatment.
(59) Methods to optimize patient radiation dose and minimize skin dose aredescribed in Chapter 5 and listed in Table 5.1, but are repeated here because of theirimportance. Limit fluoroscopy time and the number of cine frames to the least number
possible for successful completion of the procedure. Monitor patient radiation dose
during the procedure. Use fluoroscopy equipment with pulsed fluoroscopy and use thelowest pulse rate that provides adequate fluoroscopic guidance. Use the lowest
fluoroscopic and cine dose rates necessary for each stage of the procedure. Whenpossible, slightly rotate the gantry so that the entrance beam is periodically directed at adifferent entrance skin site. Keep the image receptor (image intensifier or flat panel
detector) as close as possible to the patient, and keep the x-ray tube as far away as
possible from the entrance skin site.

43

DRAFT REPORT FOR CONSULTATION
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789

1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819

3.2

Case 1 (Vliestra et al, 2004)(60) A 53-year-old man weighing 141 kg (310 lbs) had two previous percutaneoustransluminal coronary angioplasties (PTCA) 3 years earlier and now presented withunstable angina. A repeat coronary angiogram was followed immediately by PTCA ofthe distal circumflex artery. The procedure included use of the left anterior oblique(LAO) projection, biplane cinefluorography runs, high dose fluoroscopy mode and a total
fluoroscopy time of 51.4 minutes. The estimated skin dose was 22 Gy.
(61) The patient presented six weeks later with a painful, itchy rash on his lower
back in a square pattern (Fig. 3.1). This area developed into a painful ulcer.
Debridement and skin grafting were required six months after the PTCA. Local
discomfort persists.
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807

Figure 3.1 Case 1. See text for details. Reprinted from Vliestra, 2004. (Permission
needed)3.3

Case 2 (Koenig et al, 2001)(62) A 75 year old woman had two previous coronary angiograms, followed by
PTCA for a 90% stenosis of the right coronary artery. Ten months after the procedure
she developed a skin lesion (Fig. 3.2). Skin dose estimates are not available.

44

DRAFT REPORT FOR CONSULTATION

1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849

1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
Figure 3.2 Case 2. The right lateral chest demonstrates both hyper- andhypopigmentation, in addition to skin atrophy and telangiectasia. Reprinted from Koenig,
2001. (Permission needed)

3.4

Case 3 (Koenig et al, 2001)(63) A 49-year-old woman presented with an 8-year history of supraventiculartachycardia. Radiofrequency catheter ablation was performed. During the procedure her
right arm was in the x-ray beam near the port. The separator (spacer) had been removed
from the tube housing. Fluoroscopy time was approximately 20 minutes. Skin dose data
are not available. She presented 3 weeks later with a skin lesion on her right elbow (Fig.
3.3). If the patient‘s arm had been positioned outside the x-ray beam the injury could
have been prevented or its severity decreased.

45

DRAFT REPORT FOR CONSULTATION
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897

Figure 3.3 Case 3. See text for details. A) 3 weeks: Area of sharply demarcatederythema. B) 5 months: Tissue necrosis. C) 6½ months: Deep ulceration with exposure of
the bone. D) Following surgical flap. Reprinted from Koenig, 2001. (Permission
needed)3.5

Case 4 (Vliestra et al, 2004)(64) A 38-year-old man weighing 114 kg (250 lbs) was diagnosed with WolffParkinson-White syndrome. An attempt at radiofrequency ablation using biplane
fluoroscopy was unsuccessful. A few weeks after the procedure, the patient developed
areas of brownish-red discolouration on his back, which resolved. A second unsuccessful
ablation procedure was performed 2½ months later, with reappearance of the skindiscolouration after 1 week. The physician thought the skin lesion was due to thegrounding pad used for radiofrequency ablation rather than to radiation. A third
unsuccessful ablation procedure was performed; skin lesions appeared 8 days later (Fig3.4). Each of the three procedures used more than 100 min of fluoroscopy time. Skindose estimates are not available. The severe injury to the right arm was due to its
position. If the arm had been positioned away from the entrance x-ray beam, the injury
might have been avoided.
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907

46

DRAFT REPORT FOR CONSULTATION
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930

1931
1932
1933
1934
1935
1936

Figure 3.4 Case 4. The right-sided lesions show desquamation. The erythema on theback healed into discoloured scars. The right arm lesion, closer to the x-ray beam,developed necrosis and required a skin graft. Reprinted from Vliestra, 2004. (Permission
needed)3.6

Case 5 (Vañó et al, 1998)(65) A 17-year-old female underwent an electrophysiology ablation procedure forposterior pathway pre-excitation that lasted 5 hours. Eleven months later she underwent
a second procedure that also lasted 5 hours. Both procedures were performed withbiplane fluoroscopy. Fluoroscopy time for the lateral plane was estimated at 90-120
minutes. Skin dose estimates are not available. Twelve hours after the second procedure
she developed an erythematous plaque in the right axilla. One month later she consulted
a dermatologist for red macular and blister lesions on her right side. Twenty-six months
after the second procedure an indurated, atrophic plaque with linear edges, 10 x 5 cm2,
was observed (Fig. 3.5). The diagnosis was chronic radiodermatitis. The muscles in her
right arm have also been affected, with resultant limitation in the range of motion.
Because of the patient‘s age and the region irradiated, her risk of subsequent breast
cancer is also increased.

Figure 3.5 Case 5. Indurated, atrophic plaque with linear edges, with areas of hyper- andhypopigmentation. Reprinted from Vañó, 1998. (Permission needed)

47

DRAFT REPORT FOR CONSULTATION
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957

1958
1959
1960
1961
1962
1963

3.7

Case 6 (Courtesy of Dr. M. Portas, Buenos Aires, Argentina)(66) An obese 57-year-old female, a heavy smoker, underwent PTCA. The
procedure time was approximately 6 hours. No data on radiation dose are available.
Early manifestations were blisters on the skin of the back in the lumbar region. This wasdiagnosed by a dermatologist as a herpes zoster infection. Two months later, a deep ulcer(Radiation Therapy Oncology Group/European Organisation for Research and Treatmentof Cancer [RTOG/EORTC] cutaneous radiotoxicity grade 4) appeared at the same site.
(No photographs of the injury at this stage are available.) It was extremely painful. The
following year the patient underwent a plastic surgery procedure, with two rotation flaps
to close the wound. The rotation flaps subsequently underwent necrosis, leaving an ulcer
approximately 20 x 20 cm (Fig. 3.6). During the next several years, conservative
treatment was performed at a specialized burn centre. Wound coverage was performed
with porcine dermis, skin allografts and autografts, in conjunction with anti-inflammatory
and antibacterial therapy and hyperbaric oxygen treatments. This treatment led toprogressive wound closure. After 3 years of treatment (5 years after the PTCA), thedimensions of the ulcer were reduced to 3 x 1.5 cm (Fig 3.7). In vitro radiosensitivity
testing demonstrated that the patient had normal radiosensitivity. The injury andprolonged recovery were attributed to radiation exposure, obesity and heavy smoking.

Figure 3.6 Case 6. Appearance of the patient‘s back following the initial surgery andnecrosis of the rotation flaps. The ulcer is approximately 20 x 20 cm.

48

DRAFT REPORT FOR CONSULTATION
1964

1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987

Figure 3.7 Case 6. Appearance of the patient‘s back 5 years after the PTCA. After 3
years of treatment, the ulcer is reduced in size to 3 x 1.5 cm. The patient‘s quality of life
is much improved.

3.8

References

Bryk, S.G., Censullo, M.L., Wagner, L.K., Rossman, L.L., Cohen, A.M., 2006.
Endovascular and interventional procedures in obese patients: a review of procedural
technique modifications and radiation management. J. Vasc. Interv. Radiol. 17, 2733.
Koenig, T.R., Wolff, D., Mettler, F.A., Wagner, L.K., 2001. Skin injuries fromfluoroscopically guided procedures: Part 1, Characteristics of radiation injury. AJR.
Am. J. Roentgenol. 177, 3-11.
Suzuki, S., Furui, S., Isshiki, T., Kozuma, K., Koyama, Y., Yamamoto, H., Ochiai, M.,
Asakura, Y., Ikari, Y., 2008. Patients' skin dose during percutaneous coronary
intervention for chronic total occlusion. Catheter. Cardiovasc. Interv. 71, 160-164.
UNSCEAR. Sources of ionizing radiation: volume I. Report to the General Assembly,
with scientific annexes; 2010; New York, NY.
Available at:
http://www.unscear.org/unscear/en/publications/2008_1.html Accessed December
31, 2010.

49

DRAFT REPORT FOR CONSULTATION
1988
1989
1990
1991
1992
1993
1994
1995
1996

Vañó, E., Arranz, L., Sastre, J.M., Moro, C., Ledo, A., Gárate, M.T., Minguez, I., 1998.
Dosimetric and radiation protection considerations based on some cases of patientskin injuries in interventional cardiology. Br. J. Radiol. 71, 510-516.
Vlietstra, R.E., Wagner, L.K., Koenig, T., Mettler, F., 2004. Radiation burns as a severe
complication of fluoroscopically guided cardiological interventions. J Interv Cardiol
17, 1-12.

50

DRAFT REPORT FOR CONSULTATION
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019

4. PRINCIPLES OF RADIOLOGICAL PROTECTION FOR
PATIENTS AND STAFF
Main Points







Justification means that a medical procedure should only be performed when it
is appropriate for a particular patient— the anticipated clinical benefits should
exceed all anticipated procedural risks, including radiation risk.
For CT and nuclear medicine studies, justification is a responsibility shared
between the referring clinician and the cardiac imager. For fluoroscopicallyguided interventions, the responsibility rests with the interventionalist.
Optimization means that the radiation dose to the patient is suitable for the
medical purpose, and radiation that is clinically unnecessary or unproductive is
avoided.
Patient radiation dose is optimized when imaging is performed with the least
amount of radiation required to provide adequate image quality, diagnostic
information, and for fluoroscopy, adequate imaging guidance.
Dose limits apply to occupational exposure of cardiologists and staff.
Dose limits do not apply to medical exposures of patients or to carers andcomforters.
4.1

Introduction

2020
2021
2022
2023
2024
2025

(67) The Commission recommends three fundamental principles of radiologicalprotection: justification, optimization of protection, and application of dose limits (ICRP
103, ICRP 105). The first two are source related and apply to all radiation exposure
situations. The third applies to staff, but does not apply to medical exposures of patientsor to carers and comforters.
4.2
Justification

2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039

(68) The principle of justification is that, in general, ―any decision that alters theradiation exposure situation should do more good than harm. This means that byintroducing a new radiation source, by reducing existing exposure, or by reducing the riskof potential exposure, one should achieve sufficient individual or societal benefit to offset
the detriment it causes.‖ (ICRP 103, ICRP 105). The principal aim of medical exposures
is to do more good than harm to the patient, subsidiary account being taken of theradiation detriment from the exposure of the radio- logical staff and of other individuals(ICRP 103).
(69) A medical procedure should only be performed when it is appropriate for aparticular patient. The RAND Corporation has developed a definition of ―appropriate‖that is widely used: the expected health benefit (i.e., increased life expectancy, relief ofpain, reduction in anxiety, improved functional capacity) exceeds the expected negative
consequences (i.e., mortality, morbidity, anxiety of anticipating the procedure, pain
produced by the procedure, misleading or false diagnoses, time lost from work) by a51

DRAFT REPORT FOR CONSULTATION
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063

sufficiently wide margin that the procedure is worth doing (Sistrom, 2008, NHS, 1993).
In other words, the anticipated clinical benefits should exceed all anticipated proceduralrisks, including radiation risk.
(70) In the United States, appropriateness criteria have been developed for many
clinical scenarios (Brindis et al, 2005, Douglas, 2008, Patel, 2009, Hendel 2009, ACR,
2010, Taylor 2010). Similar guidelines have been developed in the United Kingdom,
though they are less readily available (RCR, 2007). European guidelines are alsoavailable (Hesse, 2005, Schroeder 2008). These recommendations are typically based ona standardized literature review and compilation of evidence tables, followed by rating ofeach indication by an expert panel with varied composition (Patel et al, 2005).
Appropriateness may vary based on national and local norms and practice patterns, aswell as well as patient and family values and preferences (Wolk et al, 2004).
(71) The responsibility for the justification of the use of a particular procedure falls
on the relevant medical practitioners (ICRP 103). For CT and nuclear medicine studies,justification is a responsibility shared between the referring clinician and the cardiac
imager. For the referring clinician, this entails weighing the benefits of a test against its
risks, including radiation exposure, and considering such an analysis for all possible
alternatives including performing no test. For the cardiac imager, justification entails
ensuring that the test has a reasonable indication, given the available information, anddiscussing the indication with the referring clinician if there is concern in this respect.
For fluoroscopically guided interventions, the responsibility rests with theinterventionalist.

2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083

(72) The principle of optimization of protection is that ―the likelihood of incurringexposures, the number of people exposed, and the magnitude of their individual doses
should all be kept as low as reasonably achievable, taking into account economic andsocietal factors. This means that the level of protection should be the best under theprevailing circumstances, maximizing the margin of benefit over harm‖ (ICRP 103, ICRP
105, NCRP 1993). This is often summarized using the acronym ALARA, which stands
for As Low As Reasonably Achievable.
(73)
For cardiology procedures, this principle is applied in the design of cardiac
facilities that use ionizing radiation, appropriate selection and use of equipment, and in
day-to-day working procedures. Optimization is best described as a radiation dose to thepatient that is suitable for the medical purpose, and avoidance of radiation that isclinically unnecessary or unproductive.
(74) Dose optimization means delivering a radiation dose to the organs and tissuesof clinical interest no greater than that required for adequate imaging and minimizing
dose to other structures (e.g., the skin). Patient radiation dose is considered to be
optimized when imaging is performed with the least amount of radiation required toprovide adequate image quality and, for fluoroscopy, adequate imaging guidance (NCI,
2005). The goal of every imaging procedure is to provide images adequate for theclinical purpose. Imaging requirements depend on the specific patient and the specificprocedure. Reducing patient radiation dose to the point where images are inadequate is

4.3

Optimization

52

DRAFT REPORT FOR CONSULTATION
2084
2085
2086
2087
2088
2089
2090

counterproductive; it results in radiation dose to the patient without answering the clinicalquestion. Improving image quality beyond what is clinically needed subjects the patientto additional radiation dose without additional clinical benefit. The goal of radiation
management is to keep patient radiation dose as low as possible consistent with the use of
appropriate equipment and the imaging requirements for a specific patient and a specificprocedure.
4.4
Dose limits

2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127

(75) The principle of application of dose limits states that ―the total dose to any
individual from regulated sources in planned exposure situations other than medical
exposure of patients should not exceed the appropriate limits recommended by theCommission‖ (ICRP 103, ICRP 105). This principle does not apply to medical exposureof patients. As noted in ICRP Publication 105, ―Provided that the medical exposures ofpatients have been properly justified and that the associated doses are commensurate withthe medical purpose, it is not appropriate to apply dose limits or dose constraints to the
medical exposure of patients, because such limits or constraints would often do more
harm than good.‖(ICRP 105) For interventional procedures, the medical condition being
treated and the non-radiation risks of the procedure typically present substantially greater
morbidity and mortality than do the radiation risks (Miller, 2008, NCRP 168, 2010).
4.5

References

What do we mean by appropriate health care? Report of a working group prepared forthe Director of Research and Development of the NHS Management Executive. Qual
Health Care 1993;2:117-23.
American College of Radiology. ACR Appropriateness Criteria®. Available at:
http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria.aspx
Accessed August 3, 2010.
Brindis RG, Douglas PS, Hendel RC, Peterson ED, Wolk MJ, Allen JM, Patel MR,
Raskin IE, Bateman TM, Cerqueira MD, Gibbons RJ, Gillam LD, Gillespie JA,
Iskandrian AE, Jerome SD, Krumholz HM, Messer JV, Spertus JA, Stowers SA.
ACCF/ASNC appropriateness criteria for single-photon emission computed
tomography myocardial perfusion imaging (SPECT MPI): a report of the American
College of Cardiology Foundation Quality Strategic Directions Committee
Appropriateness Criteria Working Group and the American Society of Nuclear
Cardiology endorsed by the American Heart Association. J Am Coll Cardiol
2005;46:1587-1605.
Douglas, P.S., Khandheria, B., Stainback, R.F., Weissman, N.J., Peterson, E.D., Hendel,
R.C., Blaivas, M., Des Prez, R.D., Gillam, L.D., Golash, T., Hiratzka, L.F.,
Kussmaul, W.G., Labovitz, A.J., Lindenfeld, J., Masoudi, F.A., Mayo, P.H.,
Porembka, D., Spertus, J.A., Wann, L.S., Wiegers, S.E., Brindis, R.G., Patel, M.R.,
Wolk, M.J., Allen, J.M., 2008. ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR
2008 appropriateness criteria for stress echocardiography: a report of the American
College of Cardiology Foundation Appropriateness Criteria Task Force, American
Society of Echocardiography, American College of Emergency Physicians,

53

DRAFT REPORT FOR CONSULTATION
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171

American Heart Association, American Society of Nuclear Cardiology, Society for
Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed
Tomography, and Society for Cardiovascular Magnetic Resonance endorsed by theHeart Rhythm Society and the Society of Critical Care Medicine. J. Am. Coll.
Cardiol.
51,
1127-1147.
Availableat:
http://content.onlinejacc.org/cgi/content/full/51/11/1127 Accessed January 1, 2011.
HendelRC,
Berman
DS,
Di
Carli
MF,
et
al.
ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 appropriate use criteria for
cardiac radionuclide imaging: a report of the American College of Cardiology
Foundation Appropriate Use Criteria Task Force, the American Society of Nuclear
Cardiology, the American College of Radiology, the American Heart Association,
the American Society of Echocardiography, the Society of Cardiovascular Computed
Tomography, the Society for Cardiovascular Magnetic Resonance, and the Society of
Nuclear Medicine. Circulation. 2009;119(22):e561-587.
Hesse, B., Tagil, K., Cuocolo, A., Anagnostopoulos, C., Bardies, M., Bax, J., Bengel, F.,
Busemann Sokole, E., Davies, G., Dondi, M., Edenbrandt, L., Franken, P., Kjaer, A.,
Knuuti, J., Lassmann, M., Ljungberg, M., Marcassa, C., Marie, P.Y., McKiddie, F.,
O'Connor, M., Prvulovich, E., Underwood, R., van Eck-Smit, B., 2005. EANM/ESC
procedural guidelines for myocardial perfusion imaging in nuclear cardiology. Eur J
Nucl
Med
Mol
Imaging
32,855-897.
Availableat:
http://www.eanm.org/scientific_info/guidelines/gl_cardio_myocard_perf.pdf
Accessed January 1, 2011.
International Commission on Radiological Protection. The 2007 Recommendations of
the International Commission on Radiological Protection. ICRP Publication 103.
Ann ICRP 2007; 37(2-4):1-332
International Commission on Radiological Protection. Radiological protection in
medicine. ICRP Publication 105. Ann ICRP 2007;37:1-63.
Miller DL. Overview of contemporary interventional fluoroscopy procedures. Health
Phys 2008; 95:638-644.
NCI. Interventional fluoroscopy: reducing radiation risks for patients and staff. NIH
Publication No. 05-5286. Bethesda:National Cancer Institute, 2005. Available at:
http://www.cancer.gov/images/Documents/45bae965-697a-4de8-9daeb77222e0e79d/InterventionalFluor.pdf Accessed January 1, 2011.
NCRP. Limitation of exposure to ionizing radiation. NCRP Report No. 116. Bethesda,
MD: National Council on Radiation Protection and Measurements; 1993.
NCRP. Radiation dose management for fluoroscopically guided interventional medical
procedures. NCRP Report No. 168. Bethesda, MD: National Council on Radiation
Protection and Measurements; 2010.
Patel MR, Spertus JA, Brindis RG, Hendel RC, Douglas PS, Peterson ED, Wolk MJ,
Allen JM, Raskin IE. ACCF proposed method for evaluating the appropriateness of
cardiovascular imaging. J Am Coll Cardiol 2005;46:1606-1613.
Patel, M.R., Dehmer, G.J., Hirshfeld, J.W., Smith, P.K., Spertus, J.A., 2009.
ACCF/SCAI/STS/AATS/AHA/ASNC 2009 Appropriateness Criteria for Coronary
Revascularization: a report by the American College of Cardiology Foundation

54

DRAFT REPORT FOR CONSULTATION
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206

Appropriateness Criteria Task Force, Society for Cardiovascular Angiography andInterventions, Society of Thoracic Surgeons, American Association for Thoracic
Surgery, American Heart Association, and the American Society of Nuclear
Cardiology Endorsed by the American Society of Echocardiography, the Heart
Failure Society of America, and the Society of Cardiovascular Computed
Tomography. J. Am. Coll. Cardiol. 53, 530-553.
Available at:
http://content.onlinejacc.org/cgi/content/full/53/6/530 Accessed January 1, 2011.
The Royal College of Radiologists. Making the best use of clinical radiology services:
referral guidelines. 6th ed. London:The Royal College of Radiologists, 2007.
Schroeder S, Achenbach S, Bengel F, et al. Cardiac computed tomography: indications,applications, limitations, and training requirements: report of a Writing Group
deployed by the Working Group Nuclear Cardiology and Cardiac CT of theEuropean Society of Cardiology and the European Council of Nuclear Cardiology.
Eur Heart J 2008;29(4):531-556.
Sistrom CL. In support of the ACR Appropriateness Criteria®. J Am Coll Radiol
2008;5:630-635.
Taylor, A.J., Cerqueira, M., Hodgson, J.M., Mark, D., Min, J., O'Gara, P., Rubin, G.D.,
Kramer, C.M., Berman, D., Brown, A., Chaudhry, F.A., Cury, R.C., Desai, M.Y.,
Einstein, A.J., Gomes, A.S., Harrington, R., Hoffmann, U., Khare, R., Lesser, J.,
McGann, C., Rosenberg, A., Schwartz, R., Shelton, M., Smetana, G.W., Smith, S.C.,
Jr.,
2010.
ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR
2010
appropriate use criteria for cardiac computed tomography: a report of the American
College of Cardiology Foundation Appropriate Use Criteria Task Force, the Societyof Cardiovascular Computed Tomography, the American College of Radiology, theAmerican Heart Association, the American Society of Echocardiography, theAmerican Society of Nuclear Cardiology, the North American Society for
Cardiovascular Imaging, the Society for Cardiovascular Angiography andInterventions, and the Society for Cardiovascular Magnetic Resonance. J. Am. Coll.
Cardiol.
56,
1864-1894.
Availableat:
http://content.onlinejacc.org/cgi/content/full/56/22/1864 Accessed January 1, 2011.inpress.
Wolk MJ, Peterson E, Brindis R, Eagle K. President's page: the appropriate cardiologist:
responsible stewardship in a golden era of cardiology. J Am Coll Cardiol
2004;44:933-935.

55

DRAFT REPORT FOR CONSULTATION
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248

5. MANAGING PATIENT DOSE IN FLUOROSCOPICALLYGUIDED INTERVENTIONS
Main Points










The informed consent process should include information on radiation risk if
the risk of radiation injury is thought to be significant.
Important aspects of the patient’s medical history that should be consideredwhen estimating radiation risk are genetic factors, co-existing diseases,
medication use, radiation history, and pregnancy.
Some of the factors that affect the patient’s radiation dose depend on the x-ray
system, but many others depend on how the operator uses the x-ray system.
During the procedure, the cardiologist should be kept aware of the fluoroscopy
time, the number of cine series and cine frames, and the total patient dose.
As patient radiation dose increases, the operator should consider the radiationdose already delivered to the patient and the additional radiation necessary tocomplete the procedure.
Patient radiation dose reports should be produced at the end of the procedure,
and archived.
Radiation dose data should be recorded in the patient’s medical record after theprocedure.
When the patient’s radiation dose from the procedure is high, clinical follow-up
is essential for early detection and management of skin injuries.
Patients who have received a substantial radiation dose should have follow-up
at 10-14 days and at one month after the procedure for possible deterministic
effects.
5.1

Introduction(76) Fluoroscopically guided interventions (FGI) comprise guided therapeutic anddiagnostic interventions, by percutaneous or other access, usually performed under local
anaesthesia and/or sedation, with fluoroscopic imaging used to localise thelesion/treatment site, monitor the procedure, and control and document the therapy(ICRP, 2000). This chapter deals with clinical radiation management before, during andafter FGI.
(77) The doses received by patients during fluoroscopically guided cardiac
procedures can be high, and some patients may have several procedures carried out in a
relatively short period of time. Hence, it is essential that the cardiologist optimises
patient radiation dose (Chambers, 2011). If a certain dose threshold is exceeded (seeChapter 2), the procedure could result in deterministic effects (harmful tissue reactions).
High radiation doses also increase stochastic risk (cancer and heritable effects).

56

DRAFT REPORT FOR CONSULTATION
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292

It is important for medical practitioners to be aware that although uncertainty remains, theabsorbed dose threshold for circulatory disease may be as low as 0.5 Gy to the heart andbrain (ICRP, 2011a). In some complex fluoroscopically guided cardiac procedures,organ doses may be > 0.5 Gy. Cardiovascular radiation effects have been reported tooccur at these doses, including focal myocardial degeneration and fibrosis, andaccelerated atherosclerosis in major blood vessels. (ICRP XXX Tissue Reactions,
2011b).
(78) The mean age of patients undergoing cardiac procedures is relatively high.
Stochastic risk is not a great concern for older patients because of the latency period forthe development of cancer and these patients‘ relatively shorter life expectancies.
Stochastic risk is of greater concern when fluoroscopically guided procedures are
performed on children. Children have longer life expectancies and are also moresensitive to the effects of radiation.
(79) Initial and continuous training in dose management and radiological protection
has a definitive influence on patient doses, and is essential for interventionalists(Hirshfeld, 2005, Rehani, 2007, ICRP 2009). Several recent publications havedemonstrated that this training helps to optimise patient dose and reduce operator dose
(Whitby, 2005, Vano, 2006, Bor, 2008, Bernardi, 2008, Kim, 2010, IAEA TECDOC
1641, 2010). Training is discussed further in Chapter 9.
5.2

Before the Procedure(80) A discussion of radiation risk is an appropriate part of the informed consent
process if radiation risk factors are present or a substantial radiation dose is anticipated.
ICRP recommends that patients should be counselled before the procedure if the risk ofradiation injury is thought to be significant (ICRP Publication 85). Important aspects ofthe patient‘s medical history that should be considered when estimating radiation risk are
genetic factors, co-existing diseases, medication use, radiation history, and pregnancy(Miller et al, 2010).
(81) Obese patients are at a higher risk of radiation-induced skin injury because ofpoor radiation penetration and the accompanying closer proximity of the x-ray source tothe patient (Bryk, 2006). Absorbed dose at the entrance skin site in obese patients can be
as much as 10 times higher than in non-obese patients (Wagner, JVIR 2000). Many of the
documented injuries associated with fluoroscopic procedures have been seen in larger
patients (Koenig Part 2, 2001).
(82) For some complex procedures, and especially when procedures are repeated inlarge or obese patients, a medical physicist can provide useful advice to help optimise theprocedure. If a previous procedure has resulted in a high peak skin dose, the strategy forfurther possible procedures in the same patient should include modifying subsequent
procedures to reduce skin dose, if possible. Other procedure modifications are often
necessary in obese patients (Bryk, 2006).
(83) Except for time-critical emergency procedures, pregnancy status should bedetermined prior to a fluoroscopically guided intervention (ICRP 105). If possible,
elective procedures on pregnant patients should be deferred until the patient is no longer

57

DRAFT REPORT FOR CONSULTATION
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336

pregnant. When medically indicated FGI procedures must be performed on pregnant
patients, and except for time-critical emergency procedures, the Commission
recommends that procedure planning include feasible modifications to minimize
conceptus dose, estimation of expected radiation dose to the conceptus, evaluation of theradiogenic risk to the conceptus, and inclusion in the informed consent process of the
expected benefits and potential risks of the procedure to both the patient and theconceptus (ICRP 84). Whenever possible, and if time permits, the pre-procedureplanning process should involve a qualified physicist.
(84) The Commission has stated that in general, termination of pregnancy at foetal
doses of less than 100 mGy is not justified based upon radiation risk (ICRP Publication
84). For comparison, a typical fetal dose from CTA of the coronary arteries isapproximately 0.1 mGy (McCollough, 2007).
5.3

During the Procedure(85) When optimizing patient radiation dose, the first priority must be to obtain asufficient number of images of a high enough quality to permit diagnosis and guideinterventions. This will require a certain minimum amount of fluoroscopy time andnumber and length of cine series. Optimal management of patient dose requires
knowledge and control of the typical fluoroscopic dose rates and values of dose per cineframe for the most common operational modes.
(86) Typical values of skin dose rate (surface entrance air kerma rate) during
cardiology procedures for a medium size patient are 15-45 mGy/min for ―medium‖
fluoroscopy mode and 50-150 mGy/min for ―high‖ fluoroscopy mode. Skin dose per cineframe is typically between 0.1 and 1.0 mGy. Skin doses in cardiac procedures can reachseveral Gy, especially for complex procedures and when several projections with similar
C-arm angulations are required (Miller, 2008). Organ doses may reach 100 Gy andeffective doses may reach 50 mSv. Variation in patient doses between centres may besubstantial. Some of this variation is likely to be due to the settings of the x-ray systems.
A study carried out by the IAEA comparing x-ray systems from different countries
demonstrated 10-fold differences for dose values when phantoms of the same thickness
were imaged (Ortiz at al, 2004).
(87) Several operational factors can substantially modify the radiation dose received
by the patients and affect the kerma-area product (KAP) and the patient‘s skin dose
(Publication 85). These are also discussed and illustrated in an ICRP publication devoted
to radiological protection outside the imaging department (reference ICRP TG 78). Someof these factors depend on the x-ray system (e.g. availability of pulsed fluoroscopy,
virtual collimation, stored fluoroscopy loops, extra filtration, wedge filters, rotational andcone beam CT acquisition modes, etc.), but others depend on how the operator uses the xray system (e.g. collimation to the area of interest, use of low fluoroscopy modes whenpossible, acquiring cine series at 12.5-15 frames per second when possible, keeping theimage detector as close as possible to the patient, avoiding steeply angulated projections,
reducing the number of frames per cine series) (NCRP Report 168, 2010).
Recommendations for dose optimization in the radiology literature apply equally to58

DRAFT REPORT FOR CONSULTATION
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380

interventional cardiology procedures (Miller, 2002, Miller, 2010, Wagner, JVIR 2000,
Wagner 2007). Table 5.1 provides some practical advice.
(88) During the procedure, the cardiologist should be aware of the fluoroscopy time,
the number of cine series and cine frames, and the total patient dose, either as KAP or as
Reference Air Kerma (RAK) the cumulative air kerma at the Interventional Reference
Point (see Glossary). (The Interventional Reference Point is also known as the Patient
Entrance Reference Point.) The need here is to monitor, in real time, whether thethreshold doses for deterministic effects are being approached or exceeded (ICRP 105,
ICRP XXX 2011b). Modern fluoroscopy systems that are compliant with theinternational standard for interventional fluoroscopy systems display radiation data to theoperator during the procedure (IEC, 2010). The responsibility for monitoring radiationdose may be delegated to a technologist, nurse or other person depending on national or
local regulations and the institution‘s policy and needs (NCRP 168, 2010). A specificindividual should be tasked with this responsibility. The purpose of dose monitoring is toensure that the operator is aware of how much radiation is being administered.
(89) As patient radiation dose increases, the operator should consider the radiationdose already delivered to the patient and the additional radiation necessary to complete
the procedure. It may be possible to reduce further radiation usage and control skin doseby limiting the number and length of cine series, decreasing the dose rate for cine or
fluoroscopy, using collimation or changing the gantry angle slightly.
(90) Knowledge of the patient‘s skin dose distribution could help to avoid the risk
of skin injuries, but measurement of skin dose distribution is not an easy task influoroscopically guided procedures. This is especially true in cardiology, where very
different C-arm angulations are used during the procedures and the regions of theirradiated skin can also be very different. However, using different C-arm angulations
can help reduce peak skin dose, especially when collimation is also used (Miller, 2002).
Figure 5.1 shows an example of skin dose distribution measured with slow film (Vano etal. 1997) and how overlap of radiation fields can increase the dose to a certain area of the
skin.
5.4

After the procedure(91) Modern fluoroscopy systems that are compliant with the international standard
for interventional fluoroscopy systems provide a dose report at the conclusion of theprocedure (IEC, 2010). An example of a typical dose report is shown in Fig 5.2. Several
companies offer dose reports for cardiology procedures that include information on skindose distribution. Patient radiation dose reports should be produced at the end of theprocedure, and archived. Radiation dose data should be recorded in the patient‘s medical
record after the procedure (Chambers, 2011).
(92) Patient doses for cardiac procedures are often reported as kerma-area product(KAP). Skin dose distribution, and especially RAK and peak skin dose (PSD) (defined in
the glossary), are sometimes more important, particularly when repeated procedures are
performed on the same patient (Miller, 2002). Fluoroscopy time does not include theeffect of fluoroscopy dose rate and does not indicate the radiation dose from cine. It is

59

DRAFT REPORT FOR CONSULTATION
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424

not a useful descriptor of patient radiation dose (Chida, 2006, Fletcher, 2002).
Fluoroscopy time should not be the only dose measurement recorded or audited(Chambers, 2011, NCRP Report 168, 2010).
(93) The management and follow-up of patients who have received a high dose ofradiation is also important. The operator should be notified promptly if the substantial
radiation dose level (SRDL) was exceeded. (SRDL is defined in the Glossary anddiscussed further in Section 10.6.) The operator should write an appropriate note in thepatient‘s medical record, stating that a substantial radiation dose has been administered,and indicating the reason (Hirshfeld, 2005). This information may be included in the
post-procedure note.
(94) When the SRDL has been exceeded, clinical follow-up is essential for early
detection and management of skin injuries (NCRP Report 168, 2010, Chambers, 2011).
The patient should be advised of the possibility of a deterministic skin injury, and should
be told to examine the beam entrance site at 2 – 4 weeks after the procedure. The
operator should be notified if any skin changes are seen. Patients should also be
contacted by telephone at approximately 30 days after the procedure. If a skin injury issuspected, the interventionalist should see the patient at an office visit, and should
arrange for appropriate follow-up care (NCRP Report 168, 2010, Chambers, 2011). The
physician responsible for the patient‘s care should be informed of the possibility ofradiation effects. Ideally, a system should be established to identify and monitor repeatedprocedures (ICRP 85, 2000).
5.5

Paediatric Patients(95) Paediatric cardiology procedures require special consideration.
These
interventions are often challenging, time-consuming and may require multi-stage
procedures, leading to high radiation exposure. Contributing factors include the higher
heart rates, smaller cardiovascular structures, small body size and wider variety ofunusual anatomic variants seen in children (Justino 2006).
(96) Patient radiation dose from paediatric interventional cardiology procedures canbe reduced by the use of dedicated radiographic protocols that include tighter collimation,pulsed fluoroscopy frame rates of 25-30 frames/sec and cine frame rates of 25-50
frames/sec. As part of the Step Lightly initiative, the Alliance for Radiation Safety inPediatric Imaging has published a checklist for use during paediatric interventional
fluoroscopy to help reduce patient doses (Sidhu, 2009).
5.6

References

American College of Radiology. ACR practice guideline for imaging pregnant or
potentially pregnant adolescents and women with ionizing radiation. Practice
Guidelines and Technical Standards 2008. Reston, VA: American College ofRadiology,
2008;p.
23-37.
Availableat:
http://www.acr.org/SecondaryMainMenuCategories/quality_safety/guidelines/dx/Pre
gnancy.aspx Accessed August 11, 2010.

60

DRAFT REPORT FOR CONSULTATION
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467

Balter S. Interventional fluoroscopy. Physics, technology and safety. Wiley-Liss, New
York, 2001.
Bernardi G, Padovani R, Morocutti G, Vano E, Malisan MR, Rinuncini M, Spedicato L,
Fioretti PM. Clinical and technical determinants of the complexity of percutaneoustransluminal coronary angioplasty procedures: analysis in relation to radiation
exposure parameters. Catheter Cardiovasc Interv 2000 Sep;51(1):1-9; discussion 10.
Bernardi G, Padovani R, Trianni A, Morocutti G, Spedicato L, Zanuttini D, Werren M,
Wagner LK. The effect of fellows‘ training in invasive cardiology on radiological
exposure of patients. Radiat Prot Dosimetry 2008, 128(1):72–76.
Bor D, Sancak T, Toklu T, Olgar T, Ener S. Effects of radiologists' skill and experienceon patient doses in interventional examinations. Radiat Prot Dosimetry 2008;129:325.
Bryk SG, Censullo ML, Wagner LK, Rossman LL, Cohen AM. Endovascular andinterventional procedures in obese patients: a review of procedural techniquemodifications and radiation management. J Vasc Interv Radiol 2006;17:27-33.
Chambers CE, Fetterly KA, Holzer R, Lin P-JP, Blankenship JC, Balter S, Laskey WK.
Radiation safety program for the cardiac catheterization laboratory. Catheter
Cardiovasc Interv 2011, in press.
Chida K, Saito H, Otani H, Kohzuki M, Takahashi S, Yamada S, Shirato K, Zuguchi M.
Relationship between fluoroscopic time, dose-area product, body weight, andmaximum radiation skin dose in cardiac interventional procedures. Am J Roentgenol.
2006;186:774-8.
Den Boer A, de Feyter PJ, Hummel WA, Keane D, Roelandt JR. Reduction of radiation
exposure while maintaining high-quality fluoroscopic images during interventional
cardiology using novel x-ray tube technology with extra beam filtering. Circulation.
1994 Jun;89(6):2710-4.
Faulkner K, Vano E. Deterministic effects in interventional radiology. Radiat Prot
Dosimetry. 2001;94(1-2):95-8.
Fletcher DW, Miller Dl, Balter S, Taylor MA. Comparison of four techniques toestimate radiation dose to skin during angiographic and interventional radiology
procedures. J Vasc Interv Radiol 2002;13:391-97.
Guibelalde E, Vano E, Gonzalez L, Prieto C, Fernandez JM, Ten JI. Practical aspects forthe evaluation of skin doses in interventional cardiology using a new slow film. Br J
Radiol. 2003 May;76(905):332-6.
Hirshfeld JW Jr, Balter S, Brinker JA, Kern MJ, Klein LW, Lindsay BD, Tommaso CL,
Tracy CM, Wagner LK, Creager MA, Elnicki M, Lorell BH, Rodgers GP, Weitz
HH; American College of Cardiology Foundation; American Heart Association;
HRS; SCAI; American College of Physicians Task Force on Clinical Competence
and Training. ACCF/AHA/HRS/SCAI clinical competence statement on physician
knowledge to optimize patient safety and image quality in fluoroscopically guided
invasive cardiovascular procedures: a report of the American College of Cardiology
Foundation/American Heart Association/American College of Physicians Task Forceon Clinical Competence and Training. Circulation. 2005;111(4):511-32.

61

DRAFT REPORT FOR CONSULTATION
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511

IAEA, 2010. Patient dose optimization in fluoroscopically guided interventional
procedures. IAEA-TECDOC-1641. Vienna: International Atomic Energy Agency,
2010.
International Commission on Radiological Protection. Radiological protection and safety
in medicine. ICRP Publication 73. Ann ICRP 1996; 26(2):1-47
International Commission on Radiological Protection. Pregnancy and medical radiation.
ICRP Publication 84. Ann ICRP 2000; 30:1-43.
International Commission on Radiological Protection. Avoidance of radiation injuries
from medical interventional procedures. ICRP Publication 85. Ann ICRP 2000;
30(2):1-67.
International Commission on Radiological Protection. The 2007 Recommendations of
the International Commission on Radiological Protection. ICRP publication 103.
Ann ICRP 2007;37:1-332.
International Commission on Radiological Protection. Radiological protection in
medicine. ICRP Publication 105. Ann ICRP 2007; 37:1-63.
ICRP, 2009. Recommendations of the International Commission on RadiologicalProtection. ICRP Publication 113, Ann. ICRP 39 (5).
International Commission on Radiological Protection 2011a.
Statement on Tissue
reactions. Approved by the Commission on April 21, 2011. ICRP ref 4825-30931464.
Availableat
http://www.icrp.org/docs/ICRP%20Statement%20on%20Tissue%20Reactions.pdf
Accessed May 9, 2011.
International Commission on Radiological Protection 2011b. Tissue Reactions and Other
Non-Cancer Effects of Radiation. ICRP Publication XXX. Ann ICRP 2011; in press
IEC. Medical electrical equipment. Part 2-43: Particular requirements for the safety of
X-ray equipment for interventional procedures. IEC 60601-2-43. 2nd edition,
Geneva, Switzerland: International Electrotechnical Commission; 2010.
Justino H. The ALARA concept in pediatric cardiac catheterization: techniques andtactics for managing radiation dose. Pediatr Radiol 2006; 36:146-153
Kim C, Vasaiwala S, Haque F, Pratap K, Vidovich MI. Radiation safety among
cardiology fellows. Am J Cardiol 2010;106(1):125-128.
Koenig TR, Mettler FA, Wagner LK. Skin injuries from fluoroscopically guided
procedures: part 2, review of 73 cases and recommendations for minimizing dosedelivered to patient. AJR Am J Roentgenol. 2001 Jul;177(1):13-20.
McCollough CH, Schueler BA, Atwell TD, Braun NN, Regner DM, Brown DL, LeRoy
AJ. Radiation exposure and pregnancy: when should we be concerned?
RadioGraphics 2007; 27:9090-918.
Miller DL, Balter S, Noonan PT, Georgia JD. Minimizing radiation-induced skin injury
in interventional radiology procedures. Radiology 2002;225:329-36.
Miller DL. Overview of contemporary interventional fluoroscopy procedures. Health
Phys 2008, 95:638-644.
Miller DL, Balter S, Schueler BA, Wagner LK, Strauss KJ, Vañó E. Clinical radiation
management for fluoroscopically guided interventional procedures. Radiology 2010,
in press.

62

DRAFT REPORT FOR CONSULTATION
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555

Neofotistou V, Vano E, Padovani R, Kotre J, Dowling A, Toivonen M, Kottou S,
Tsapaki V, Willis S, Bernardi G, Faulkner K. Preliminary reference levels ininterventional cardiology. Eur Radiol. 2003 Oct;13(10):2259-63.
National Council on Radiation Protection and Measurements. Radiation dosemanagement for fluoroscopically guided interventional medical procedures. NCRP
Report No. 168. Bethesda, MD: National Council on Radiation Protection andMeasurements; 2010.
Neofotistou V. Review of patient dosimetry in cardiology. Radiat Prot Dosimetry.
2001;94(1-2):177-82.
Ortiz P, Vano E, Padovani R, Cotelo E, Ramirez A, Mota H, Faulkner K, Balter S.
Influence of the interventional equipment performance on patient dose and image
quality. Results of a survey under the IAEA International Action Plan for theRadiological Protection of Patients. ECR 2004. Vienna. Austria.
Rehani MM. Training of interventional cardiologists in radiation protection—the
IAEA‘s initiatives. Int J Cardiol 2007;114:256-260.
Sidhu MK, Goske MJ, Coley BJ, Connolly B, Racadio J, Yoshizumi TT, Utley T,
Strauss KJ. Image gently, step lightly: increasing radiation dose awareness inpediatric interventions through an international social marketing campaign. J Vasc
Interv Radiol 2009; 20:1115-1119.
Tsapaki V, Kottou S, Kollaros N, Dafnomili P, Kyriakidis Z, Neofotistou V. Dose
performance evaluation of a charge coupled device and a flat-panel digital
fluoroscopy system recently installed in an interventional cardiology laboratory.
Radiat Prot Dosimetry. 2004;111(3):297-304.
Tsapaki V, Kottou S, Vano E, Faulkner K, Giannouleas J, Padovani R, Kyrozi E,
Koutelou M, Vardalaki E, Neofotistou V. Patient dose values in a dedicated Greek
cardiac centre. Br J Radiol. 2003 Oct;76(910):726-30.
Vano E, Arranz L, Sastre JM, Moro C, Ledo A, Garate MT, Minguez I. Dosimetric andradiation protection considerations based on some cases of patient skin injuries ininterventional cardiology. Br J Radiol. 1998 May;71(845):510-6.
Vano E, Goicolea J, Galvan C, Gonzalez L, Meiggs L, Ten JI, Macaya C. Skin radiation
injuries in patients following repeated coronary angioplasty procedures. Br J Radiol.
2001 Nov;74(887):1023-31.
Vano E, Gonzalez L, Ten JI, Fernandez JM, Guibelalde E, Macaya C. Skin dose anddose-area product values for interventional cardiology procedures. Br J Radiol. 2001
Jan;74(877):48-55.
Vano E, Gonzalez L. Approaches to establishing reference levels in interventional
radiology. Radiat Prot Dosimetry. 2001;94(1-2):109-12.
Vano E, Guibelalde E, Fernandez JM, Gonzalez L, Ten JI. Patient dosimetry ininterventional radiology using slow films. Br J Radiol. 1997 Feb;70:195-200.
Vano E, Prieto C, Fernandez JM, Gonzalez L, Sabate M, Galvan C. Skin dose and dosearea product values in patients undergoing intracoronary brachytherapy. Br J Radiol.
2003 Jan;76(901):32-8.
Vano E, Gonzalez L, Fernandez JM, Alfonso F, Macaya C.Occupational radiation doses
in interventional cardiology: a 15-year follow-up. Br J Radiol. 2006;79(941):383-8.

63

DRAFT REPORT FOR CONSULTATION
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572

Vlietstra RE, Wagner LK, Koenig T, Mettler F. Radiation burns as a severe complicationof fluoroscopically guided cardiological interventions. J Interv Cardiol. 2004
Jun;17(3):131-42.
Wagner LK and Archer BR. Minimising risks from fluoroscopic x rays. Third Edition.
Partners in Radiation Management (R.M. Partnership). The Woodlands, TX 77381.
USA 2000.
Wagner LK, Archer BR, Cohen AM. Management of patient skin dose influoroscopically guided interventional procedures. J Vasc Interv Radiol 2000;11:2333.
Wagner LK. Radiation injury is a potentially serious complication to fluoroscopicallyguided complex interventions. In: Biomedical Imaging and Intervention Journal.
Lumpur, Malaysia: Dept. of Biomedical Imaging, University of Malaya; 2007:e22.
Available at http://www.biij.org/2007/2/e22/ Accessed Aug 9, 2010
Whitby M, Martin CJ. A study of the distribution of dose across the hands ofinterventional radiologists and cardiologists. Br J Radiol 2005;78:219-29.

64

DRAFT REPORT FOR CONSULTATION
2573
2574
2575
2576
2577

Figure 5.1
Example of skin dose distribution in cardiology procedures (measured with slow film at
the San Carlos University Hospital in Madrid). Skin dose distribution measured during a
conventional PTCA. In this case the peak skin dose was 0.4 Gy.

2578
2579
2580
2581

65

DRAFT REPORT FOR CONSULTATION
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592

Figure 5.2
Example of a patient dose report produced by a Siemens Axiom Artis X ray system.
Entries 1 to 5 indicate the series acquisition order. CARD is the name of theacquisition protocol. FIXED means a constant frame rate during the series run. Coro
LD is the acquisition mode. Time in seconds is the duration of the series. Series frame
rate, date, time of acquisition, kV, mA peak, pulse time, focus size, extra copper
filter, KAP per series, RAK, X-ray beam angulation, and number of frames (for eachseries) are reported. Total fluoroscopy time, total KAP, and total RAK are also given
at the end of the report. The original printing format of the X-ray system ismaintained.

2593
2594

2595
2596
2597
2598

66

DRAFT REPORT FOR CONSULTATION
2599
2600
2601
2602
2603

Table 5.1
Practical advice to reduce patient doses.

Techniques toreduce patient dose
Use a low-dose fluoroscopy mode when possible
Use the lowest-dose mode for image (cine) acquisition that is compatible with therequired image quality
Minimize fluoroscopy time—use fluoroscopy only to guide devices and observe
motionUse the last-image-hold image for review when possible, instead of using
fluoroscopy
When possible, store a fluoroscopy loop instead of performing a cine run
If it is available, use a stored fluoroscopy loop for review instead of using
fluoroscopy
Minimize the number of cine series
Minimize the number of frames per cine series
Never use cine as a substitute for fluoroscopy
Collimate the radiation beam to the area of interest
Use virtual collimation if it is available
Use wedge filters when they are appropriate
Keep the image detector (image intensifier or flat detector) as close as possible to thepatient.
Keep the patient as far as possible from the x-ray tube.
Try to avoid steeply angulated projections (especially LAO cranial)
Try to vary the C-arm angulation slightly, to avoid concentrating the radiation doseat a single site on the patient‘s skin.
Use magnification only when necessary.
Remember that for large patients, and also for steeply angulated projections, thedose to the patient increases substantially.
Pay attention to the patient radiation dose display in the procedure room.
If the patient has had previous similar procedures, try to obtain information about theprevious radiation doses to optimise subsequent procedures.
2604
2605

67

DRAFT REPORT FOR CONSULTATION
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645

6. RADIATION DOSES AND PROTECTION OF STAFF DURING
INTERVENTIONAL FLUOROSCOPY
Main Points








In general, reducing patient dose will also reduce operator dose.
The basic tools of occupational radiological protection are time, distance andshielding.
The use of personal protective shielding is necessary in the cardiac
catheterization laboratory.
Radiological protection for the eyes is necessary for interventionalists.
Occupational doses can be reduced to very low levels if ceiling suspended lead
screens and protective lead curtains suspended from the side of the proceduretable are used properly.
Radiation exposure to the operator is neither uniform nor symmetric.
Proper use of personal monitoring badges is necessary in cardiac
catheterization laboratories in order to monitor and audit occupationalradiation dose.
6.1

Introduction(97) Despite regulatory limits on occupational dose, there have been reports ofcataracts and of fairly high radiation doses to the hands and legs of staff and hair loss inthe portions of the legs not shielded by a protective device (Balter, 2001a). The
occurrence of radiation-induced cataracts in operators (Vano et al. 1998a, Vano et al,
2010, ICRP 2000, Ciraj-Bjelac, 2010) and the debate regarding the incidence of brain
cancer in interventional cardiologists (Finkelstein, 1998, Klein et al, 2009) highlight theimportance of occupational radiological protection for interventionalists, especially forparts of the body not protected by the lead apron.
(98) The operator is not normally exposed to the x-ray beam directly, but is exposed
to a considerable amount of scatter radiation. There are a number of techniques,described in Chapter 5, and protective devices, discussed in this Chapter, that, if usedappropriately, should result in the operator‘s annual effective dose being well within
regulatory limits. With proper use of radiological protection tools and techniques, theeffective dose (E) for an interventionalist is typically 2–4 mSv/year, and is well below the
20 mSv/year limit recommended by the Commission (Dendy, 2008, Tsapaki, 2004,
Miller, 2010, ICRP 2007). Proper use of personal monitoring badges is essential in
cardiac catheterization laboratories in order to monitor and audit occupational radiation
dose. Too often, personal monitoring badges are not worn, or are worn improperly(Padovani, 2011). Training in radiation management and radiological protection, as
discussed in Chapter 9, is essential (ICRP 2000).

68DRAFT REPORT FOR CONSULTATION
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687

6.2

Comparison of radiation exposure with that of other staff(99) The interventionalist encounters much more radiation than most other medical
and paramedical staff in a hospital. The radiation intensity from radioisotopes used innuclear medicine is smaller by a factor of a few tens or even hundred. Nuclear medicine
staff are likely to be exposed to much less radiation, whether it emanates from the patientor from external sources (normally in shielded containers). Similarly, while the radiation
sources used in radiotherapy are of very high strength (GBq or TBq of radioactivity),
staff are exposed only to remnant radiation leaking through the shielding material andscattered through a large distance. Staff in the interventional laboratory who arepositioned in the control room are protected by both shielding and distance from the x-ray
beam. Typically, in a properly designed facility, the radiation intensity in the control
room may be tens of thousands of times less than at the operator‘s position (Rehani and
Ortiz-Lopez, 2005). Exposure factors for the interventionalist are a thousand times higher
than for staff working in the control room.
(100) The major protection in nuclear medicine accrues from the lower radiation
intensity and in radiotherapy from shielding and distance. The situation in interventional
fluoroscopy is very different. First, the operator‘s working position is quite close to the xray source and the source of scatter radiation (the patient). Second, the intensity of the xray beam lies in between the radiation intensities observed in nuclear medicine andradiotherapy. Also, beam intensity is 10-fold or 20-fold higher in cine mode than influoroscopy mode (NCRP Report 168, 2010). Shielding plays a major role in radiologicalprotection in interventional fluoroscopy, due to variability in the operator‘s distance fromthe x-ray source, the relative position of the operator, patient, and x-ray source and theduration of the procedure.
6.3

The essentials of occupational radiological protection(101) The essentials of occupational radiological protection are time, distance andshielding. Staff radiological protection cannot be handled independently from patient
protection, since they correlate in many ways. Both patient and occupational radiologicalprotection are also discussed in an ICRP publication devoted to radiological protection
outside the imaging department (reference ICRP TG 78). In general, reducing patient
dose will also reduce operator dose.
(102) Time, one essential component of radiological protection, is controlled by
reducing the time the x-ray beam is on, both for fluoroscopy and for cine. Reducing
fluoroscopy time and fluoroscopy dose rate reduces patient dose. Reduced patient dose
results in reduced scatter, and therefore in reduced operator dose. Readers are advised toremember all of the factors discussed in Chapter 4.
(103) Distance is a valuable tool for radiological protection. Radiation dose
decreases as the square of the distance between the radiation source and the operator (theinverse square law). A person who moves away from the x-ray source to three times theoriginal distance will receive only one-ninth of the original dose. During a procedure, theoperator cannot normally move further away from the patient than arm‘s length. This can
69

DRAFT REPORT FOR CONSULTATION
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731

result in high operator radiation doses, especially if contrast medium is injected manuallyfor angiographic runs. However, if a mechanical injector is used for contrast medium
injection, the operator can move back away from the patient, and ideally behind a shield.
(104) In general, scattered radiation is most intense on the entrance beam side of thepatient (Balter, 2001b, Schueler et al, 2006, Stratakis et al, 2006). When using a C-armin a lateral projection, the operator should be positioned on the image receptor side of thepatient, if possible. When using a C-arm in a frontal projection, positioning the x-ray
tube below the table will place the area of higher radiation scatter towards the floor, sothat the operator‘s head and neck receive less radiation.
(105) Shielding is of three types: architectural shielding, equipment mounted shields,
and personal protective devices (Miller et al, 2010). Architectural shielding is built into
the walls of the procedure room and is not discussed further here. Rolling and stationary
shields that are constructed of transparent leaded plastic and rest on the floor are usefulfor providing additional shielding for both operators and staff. They are particularly well
suited for use by nurses and anaesthesia personnel. The interventionalist is protected byequipment-mounted shields suspended from the ceiling and the procedure table, and by
personal protective devices such as a lead apron, leaded glasses and a thyroid shield.
(106) Simple measures, such as standing a little away from the table and patient,
limiting the field size (collimation) and carrying out procedures quickly consistent withcase complexity can be very effective in reducing occupational radiation dose. Table 6.1
presents some practical advice to improve occupational protection in the catheterizationlaboratory and Table 6.2 presents the relative change in scatter dose rates measured in a
typical catheterization laboratory for different changes in technique. The values in Table
6.2 highlight the large changes in scatter dose associated with changes in technique andpatient body size.
6.4
Personal protective devices(107) The use of personal protective shielding is essential in the cardiac
catheterization laboratory. In the past, there has been a trend to use lead aprons of higher
lead equivalence (0.5 mm rather than 0.25, 0.3 or 0.35 mm), even though physicalmeasurements did not demonstrate a great difference in attenuation (Table 6.3). The
inherently conservative safety factor has always influenced practice in radiation, both forinterventionalists and for regulators.
(108) When procedures are performed on thinner patients, and in particular on
children, a lead apron of 0.25 mm lead equivalence will suffice for staff protection, but
for procedures performed on thicker patients, and for procedures performed by physicianswith heavy workload, a 0.5 mm lead apron may be more suitable. Lead is very effective
for protecting against radiation, but is heavy. The weight can cause problems for staff
who have to wear these aprons for long spans of time (Goldstein, 2004). There are reportsof back injuries due to lead aprons among staff who wear these aprons for many years(NCRP, 2010). Some newer aprons are lighter weight while maintaining approximately
the same lead equivalence. Newer apron designs distribute weight using a variety ofdifferent methods. Two-piece (skirt and vest) wraparound aprons distribute the apron‘sweight and also provide protection for the wearer‘s back.

70

DRAFT REPORT FOR CONSULTATION
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774

(109) Lead aprons should be properly placed on designated hangers and should not
be folded, creased, or crumpled in any way. Sitting on them, folding them or improperly
hanging them may result in damage that reduces their effectiveness. Lead aprons, gloves
and other leaded protective clothing should be inspected before they are put into service
and then periodically re-inspected to determine that they provide the shielding benefit for
which they were designed. A combination of visual, physical and fluoroscopic inspection
can be employed to ensure the integrity of the garments. Consideration should be given tominimizing the irradiation of inspectors by minimizing unnecessary fluoroscopy (NCRP
168, 2010).
(110) A lead apron does not protect the eyes, the hands, the lower legs or the back(unless the apron is the wrap-around type). Radiation exposure of these parts of the
body has become a concern.
(111) Radiological protection for the eyes is essential for interventionalists (Dauer etal, 2010). Preferably, this protection is provided by ceiling-suspended shields (section
6.3), as these devices protect the entire head, and not just the eyes. However, there aremany procedures where it is not practical to use ceiling-suspended shields, as theyinterfere with the operator‘s ability to perform the procedure (Miller et al., 2010). In
these situations, leaded eyeglasses should be worn. Wearing these eyeglasses has beenshown to significantly reduce radiation dose to the operator‘s eyes (Vano et al, 2008;
Thornton et al, 2010).
(112) While the dose reduction factor for 0.5 mm lead equivalent protective glasses
is approximately 0.03 (i.e., 97% of the radiation is attenuated) the extent of radiation
attenuation by the eyeglass lenses is not an adequate descriptor, by itself, of theeffectiveness of the eyewear (NCRP report 168, 2010). For maximum effectiveness,radiation protective eyewear should intercept as much as possible of the scatteredradiation that is directed at the interventionalist‘s eyes. During interventional procedures,interventionalists normally turn their heads away from the primary beam to view thefluoroscopy monitor. This results in exposure of the eyes to scattered radiation from theside. Protective eyewear should provide shielding for side exposure, using either sideshields or a wrap-around design (NCRP report 168, 2010). Proper fit is necessary toensure that the lenses and side shields adequately protect the eye and minimize exposure,and is also important to minimize discomfort from the weight of the eyewear (Schueler etal., 2009). Even properly designed and fitted leaded eyewear attenuates scatteredradiation by only a factor of 2 or 3 (Moore et al., 1980; Thornton et al, 2010). The net
effect of protective eyeglasses is dependent on the design of the glasses, the nature of theclinical procedure, and the wearer‘s work habits.
(113) In younger individuals, the thyroid gland is relatively sensitive to radiationinduced cancer. However, the cancer incidence risk is strongly dependent on age at
exposure, with very little risk after age 30 for males and age 40 for females (NRC, 2006).
For younger workers, wearing a thyroid collar and a protective apron reduces effective
dose to ~50 % of the effective dose achieved by wearing a protective apron alone(Martin, 2009; von Boetticher et al., 2009). Use of a thyroid collar (or a protective apron
with thyroid coverage) is recommended for younger interventionalists and for all71

DRAFT REPORT FOR CONSULTATION
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817

personnel whose personal monitor readings at the collar level (unshielded) exceed 4 mSv(E) in a month (Wagner, 2004).
(114) Flexible, sterile, radiation-attenuating surgical gloves are available to reduce
interventionalist hand exposure. A previous recommendation that protective gloves beworn in high exposure situations has been reconsidered (NCRP report 133, 2000, NCRP
report 168, 2010). Attenuating surgical gloves may be used to provide a small degree ofprotection when hands are exposed only to scattered radiation, but the use of these gloves
does not permit interventionalists to place their hands safely in the primary beam (NCRP
168, 2010).
(115) There are several factors that could lead to higher hand doses forinterventionalists when these gloves are used (Miller et al, 2010). Just as with special
tools that allow for increased distance between the hands of the interventionalist and theprimary x-ray beam, the reduction in tactile feedback from radiation-attenuating surgicalgloves may lead to an increase in fluoroscopy time or CT exposure time for delicate
procedures. Because of the increased dose when any shielding is placed in the primarybeam, and the false sense of security that these gloves provide, protective gloves canresult in increased radiation dose to the hand when the gloved hand is in the primarybeam (Wagner, 1996). With or without added protection, the hands should not be placedin the primary x-ray beam, except for those rare occasions when it is essential for thesafety and care of the patient. This should be done for the shortest possible time. As arule, if an operator‘s hands are visible on the monitor, then practices should be altered(Limacher et al. 1998).
6. 5

Equipment-mounted shields(116) The standard equipment-mounted shields used in catheterization laboratories atpresent are ceiling suspended lead screens and protective lead curtains suspended fromthe side of the procedure table. If these tools are used properly, occupational doses can be
reduced to very low levels.
(117) A leaded glass or plastic screen placed between the patient and the operator
protects the operator‘s eyes, head and neck. Properly placed shields have been shown todramatically reduce operator eye dose (Maeder et al., 2006, Thornton et al, 2010). These
screens can effectively replace both leaded eyewear and a thyroid shield. The screens
add no weight to the operator, eliminating the ergonomic consequences of the protective
equipment they replace.
(118) When a frontal (posteroanterior) projection is used and the x-ray tube is below
the procedure table, scatter dose rates under the table are 3-4 times higher than the values
over the table (Schueler et al, 2006). Leaded curtains suspended from the procedure tableshould be used to protect the interventionalist‘s lower legs. At present, these shields areavailable in almost all interventional suites.
(119) Disposable, lightweight, sterile, lead-free radiological protection drape or padshields can be positioned on the patient outside of the beam path to significantly reduce
scattered radiation during cardiac interventional procedures (Sawdy et al, 2009, Germano
et al, 2005). These contain metallic elements (typically bismuth or tungsten-antimony)and are placed on the patient after the operative site has been prepared and draped. They72

DRAFT REPORT FOR CONSULTATION
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859

have been shown to reduce operator dose substantially, with reported reductions of 12fold for the eyes, 26-fold for the thyroid and 29-fold for the hands (King et al, 2002,
Dromi et al, 2006). While their use adds some cost to the procedure, disposable
protective drapes should be considered for complex procedures and procedures where theoperator‘s hands must be near the radiation field (e.g., pacemaker placement) (Miller etal., 2010). In some institutions they are used routinely (Kim et al, 2010). These drapes
should not be visible in the fluoroscopic image. If they are, the result will be an increasein patient dose.
6.6

Overall impact of protective devices(120) The effective dose (E) to the cardiologist per procedure has been reported torange from 0.2 to 18.8 Sv (Padovani and Rodella, 2001). A more recent review
demonstrated a range of 0.02 to 38.0 Sv (Kim et al, 2008). The wide dose ranges aremost likely due to both the wide variation in procedure complexity and the inconsistentuse of shields and personal protective devices. Modest operator dose reductions overtime were observed for both diagnostic catheterizations and ablation procedures, due totechnological improvements, but doses were not reduced over time for percutaneous
coronary interventions. This was believed to be due mainly to the increased complexityof interventions.
(121) Even if one assumes a rather high workload of 1000 angiographic procedures
per year, the annual threshold level of 20 mSv will rarely be exceeded. One study
reported an estimate of E for the operator of only 0.04–0.05 mSv/year (Efstathopolous etal. 2003), although other studies have reported 2–4 mSv/year (Dendy, 2008, Tsapaki,2004). The extensive studies by Kuon et al. establish that with proper choice of techniqueand shielding devices, the operator may be exposed to only 0.8% of typical radiationlevels in advanced cardiac catheterization laboratories (Kuon et al. 2002).
(122) When a lateral projection or steep gantry angulation is used, standing on the xray tube side of the C-arm increases operator dose. Kuon et al. have estimated theinfluence of angulation of the X-ray tube on the amount of scatter radiation to theoperator (Kuon et al. 2004). Radiation levels have been found to be highest for the left
anterior oblique (LAO) position, whereas in posteroanterior (PA) and right anterior
oblique (RAO) angulations, levels are much lower (Kuon et al. 2002, 2003, 2004).
Simultaneous craniocaudal angulation further increases the dose. The group has shownthat the standard view for the left main stem coronary artery (LAO 60°/20°–) isassociated with a 7.6-fold increase in dose to the operator and a 2.6-fold increase in dose
for the patient as compared to an alternative less frequently used angulation (caudal
PA0°/30°–).
(123) Effective dose does not reflect the doses to susceptible, unprotected parts of thebody—the hands and the eyes. Radiation exposure to the operator is neither uniform nor
symmetric. A right-handed operator performing the procedure via the right femoral
artery has his or her left side turned towards the patient. Therefore the left side of the
body is exposed to the highest level of scatter radiation (Maeder et al. 2005). This isespecially true for the hands, which are at the level where the X-ray beam enters the73DRAFT REPORT FOR CONSULTATION
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869

patient. During cardiac catheterization, the left hand has been reported to receive twice
the dose as compared with the right hand (Vaño et al. 1998b). The left eye also receives
higher doses than the right eye. Not surprisingly, a tall operator will receive a lower eyedose than a short operator, because of the greater distance from the tall operator‘s eyes tothe patient.
(124) Unless personal monitoring devices are always worn, and worn properly, it is
not possible to estimate occupational dose accurately. Failure to wear personalmonitoring devices may lead to the false belief that an individual‘s occupational dose is
low when it is not.
6.7
Personal dosimetry

2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902

(125) The Commission recommends the use of two personal dosimeters foroccupational dosimetry cardiac catheterization laboratories: one worn on the trunk of the
body inside the apron and the other worn outside the apron at the level of the collar or theleft shoulder (ICRP 2000). The dosimeter under the apron provides an estimate of thedose to the organs of the shielded region. The dosimeter worn outside the apron supplies
an estimate of the dose to the organs of the head and neck, including the thyroid and lensof the eyes (if unshielded), but greatly overestimates the doses to organs of the trunk.
Results obtained from both dosimeters can be used to estimate the occupational effective
dose as recommended by the NCRP (NCRP, 1995) and ICRP (ICRP, 2000). A dosimeterfor the hands may also be useful.
(126) The effective dose, E, can be estimated from the dosimeter values for H w(under the apron at the waist, although this position is not critical) and Hn (above theapron at the neck) from the equation:
E = 0.5 Hw + 0.025 Hn(127) NCRP report 122 (NCRP 1995) contains specific recommendations forcalculating the effective dose when protective aprons are worn during diagnostic andinterventional medical procedures involving fluoroscopy. In addition to the above
formula, it states that the effective dose can be estimated as Hn/21 if only one dosimeter
is worn on the neck outside the apron.
(128) The European Commission DIMOND project addressed the issues regarding
optimization of staff doses with an attempt to propose preliminary occupational dose
constraints (Tsapaki at al. 2004). The proposed value for cardiologists' annual effective
dose was 0.6 mSv. UNSCEAR (UNSCEAR 2000, paragraph 166) reported thatcardiologists tend to be the most exposed staff in medicine; their average annual dose was
0.4mSv, and an appreciable proportion received more than 1 mSv. A recent review ofradiation exposures to operators from cardiac procedures over a 30 year period
highlighted the difficulty in comparing reported dosimetry results because of significant
differences in dosimetric methods in each study (Kim et al, Health Physics, 2008). Better
standardization of dosimetric methods is recommended.
(129) Many operators not only do not use protective equipment properly, but also do
not regularly wear their dosimeters. Failure to wear dosimeters is a problem throughout

74DRAFT REPORT FOR CONSULTATION
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945

the world (Vaño et al. 1998b, McCormick, 2002, Padovani, 2011). In addition tomonitoring personal exposure, dosimeter use helps to increase awareness about
radiological protection. In the absence of formal training in radiological protection for
cardiologists in such countries, physicians in training adopt the practices of their seniors(Rehani and Ortiz-Lopez, 2005).
(130) Compliance with the radiation badge policies is one of the main problems inmany interventional cardiology services (Vano 2005). Reported occupational dose values
are often surprisingly low, and the reason is likely not a high level of radiologicalprotection, but rather failure to wear personal dosimeters. McCormick et al. (McCormick2002) reported that before a mandatory radiological protection training programme,
compliance with the radiation badge policy for physicians and nurse clinicians was only
36% in 1999, and afterwards reached a maximum of only 77%. A strict policy on theregular use of personal dosimeters should be part of any quality programme in cardiology
laboratories.
6.8

References

Balter, S, 2001a. Interventional fluoroscopy – physics, technology, safety. Wiley-Liss,
New York.
Balter S., 2001b. Stray radiation in the cardiac catheterization laboratory. Radiat Prot
Dosim 94(1-2), 183-188.
Ciraj-Bjelac O, Rehani MM, Sim KH, Liew HB, Vano E, Kleiman NJ. Risk for radiationinduced cataract for staff in interventional cardiology: Is there reason for concern?
Catheter Cardiovasc Interv 2010;76(6):826-834.
Dauer, L.T., Thornton, R.H., Solomon, S.B., St Germain, J., 2010. Unprotected operator
eye lens doses in oncologic interventional radiology are clinically significant:estimation from patient kerma-area-product data. J. Vasc. Interv. Radiol. 21, 18591861.
Dendy PP. Radiation risks in interventional radiology. Br J Radiol 2008; 81:1-7.
Dromi, S., Wood, B.J., Oberoi, J., Neeman, Z., 2006. Heavy metal pad shielding during
fluoroscopic interventions. J. Vasc. Interv. Radiol. 17, 1201-1206.
Efstathopoulos E, Makrygiannis SS, Kottou S, et al. Medical personnel and patient
dosimetry during coronary angiography and intervention. Phys Med Biol
2003;48:3059-68.
Finkelstein MM. Is brain cancer an occupational disease of cardiologists? Can J Cardiol
1998;14,1385-8.
Germano, J.J., Day, G., Gregorious, D., Natarajan, V., Cohen, T., 2005.
A novel radiation protection drape reduces radiation exposure during fluoroscopy guided
electrophysiology procedures. J. Invasive Cardiol. 17, 469-72.
Goldstein JA, Balter S, Cowley M, Hodgson J, Klein LW; Occupational hazards ofinterventional cardiologists: prevalence of orthopedic health problems incontemporary practice. Catheter Cardiovasc Interv. 2004 Dec;63(4):407-11.
ICRP. Avoidance of radiation injuries from medical interventional procedures. ICRP
Publication 85. Ann ICRP 2000;30(2).

75DRAFT REPORT FOR CONSULTATION
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989

ICRP. The 2007 Recommendations of the International Commission on RadiologicalProtection. ICRP Publication 103. Ann ICRP 2007; 37(2-4):1-332
Kim KP, Miller DL, Balter S, Kleinerman RA, Linet MS, Kwon D, Simon SL.
Occupational radiation doses to operators performing cardiac catheterization
procedures. Health Phys 94: 211-227, 2008.
Kim, C., Vasaiwala, S., Haque, F., Pratap, K., Vidovich, M.I., 2010. Radiation safety
among cardiology fellows. Am. J. Cardiol. 106, 125-128.
King JN, Champlin AM, Kelsey CA, Tripp DA. Using a sterile disposable protective
surgical drape for reduction of radiation exposure to interventionalists. Am J
Roentgenol 2002; 178:153-157.
Klein LW, Miller DL, Balter S, Laskey W, Haines D, Norbash A, Mauro MA, Goldstein
JA. Occupational health hazards in the interventional laboratory: time for a safer
environment. Heart Rhythm 2009, 6:439-444.
Kuon E, Schmitt M, Dahm JB. Significant reduction of radiation exposure to operator
and staff during cardiac interventions by analysis of radiation leakage and improved
lead shielding. Am J Cardiol 2002; 89:44-9.
Kuon E, Dahm J, Empen K, et al. Identification of less-irradiating tube angulations ininvasive cardiology. J Am Coll Cardiol 2004;44:1420-8.
Limacher MC, Douglas PS, Germano G, et al. ACC expert consensus document.
Radiation safety in the practice of cardiology. J Am Coll Cardiol. 1998;31:892-913.
Maeder M. Verdun FR, Stauffer JC et al. Radiation exposure and radiation protection ininterventional cardiology. Kardiovaskuläre Medizin 2005;8:124-132.
Maeder M, Brunner-La Rocca HP, Wolber T, Ammann P, Roelli H, Rohner F, Rickli H.
Impact of a lead glass screen on scatter radiation to eyes and hands in interventional
cardiologists. Catheter Cardiovasc Interv 2006; 67:18-23.
Marshall NW, Faulkner K, Clarke P. An investigation into the effect of protective
devices on the dose to radiosensitive organs in the head and neck. Br J Radiol. 1992
Sep;65(777):799-802.
Martin, CJ. A review of radiology staff doses and dose monitoring requirements. Radiat
Prot Dosim 2009; 136(3), 140-157.
McCormick VA, Schultz CC, Hollingsworth-Schuler V, Campbell JM, O‘Neill WW,
Ramos R. Reducing radiation dose in the cardiac catheterization laboratory bydesign alterations and staff education. Am J Cardiol 2002; 90:903-905.
Miller DL, Vañó E, Bartal G, Balter S, Dixon R, Padovani R, Schueler B, Cardella JF,
de Baère T. Occupational radiation protection in interventional radiology: A joint
guideline of the Cardiovascular and Interventional Radiology Society of Europe andthe Society of Interventional Radiology. Cardiovasc Interv Radiol 2010; 33:230239.
Moore WE, Ferguson G, Rohrmann C. Physical factors determining the utility ofradiation safety glasses. Med Phys 1980; 7(1), 8-12.
NRC. Health risks from exposure to low levels of ionizing radiation: Phase 2, BEIR VII.
Washington, DC: The National Academies Press, 2006.
NCRP. Use of personal monitors to estimate effective dose equivalent and effective dose
to workers for external exposure to low-LET radiation. NCRP report No. 122.

76

DRAFT REPORT FOR CONSULTATION
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032

Bethesda, Maryland: National Council on Radiation Protection and Measurements;
1995.
NCRP. Radiation protection for procedures performed outside the radiology department.
NCRP Report No. 133. Bethesda, Maryland: National Council on Radiation
Protection and Measurements; 2000.
NCRP. Radiation dose management for fluoroscopically guided interventional medical
procedures. NCRP Report No. 168. Bethesda, MD: National Council on Radiation
Protection and Measurements; 2010.
Padovani R, Rodella CA. Staff dosimetry in interventional cardiology. Radiat Prot
Dosimetry 2001;94:99-103.
Padovani, R., Le Heron, J., Cruz-Suarez, R., Duran, A., Lefaure, C., Miller, D.L., Sim,
H.K., Vano, E., Rehani, M., Czarwinski, R., 2010. International project on individual
monitoring and radiation exposure levels in interventional cardiology. Radiat Prot
Dosimetry 2011; in press.
Rehani MM, Ortiz-Lopez P. Radiation effects in fluoroscopically guided cardiac
interventions – keeping them under control.(Editorial). Int J Cardiol 2006; 109(2):147-151.
Sawdy, J.M., Gocha, M.D., Olshove, V., Chisolm, J.L., Hill, S.L., Phillips, A.,
Galantowicz, M., Cheatham, J.P., Holzer, R.J., 2009. Radiation protection duringhybrid procedures: innovation creates new challenges. J. Invasive Cardiol. 21, 43740.
Schueler BA, Vrieze TJ, Bjarnason H, Stanson AW. An investigation of operator
exposure in interventional radiology. RadioGraphics 2006; 26(5), 1533-1541.
Schueler BA, Sturchio G, Landsworth R, Hindal M, Magnuson D. (2009) Does newlightweight leaded eyewear provide adequate radiation protection for fluoroscopists?
(abstract) Med Phys 2009; 36(6), 2747-2748.
Stratakis J, Damilakis J, Hatzidakis A, Theocharopoulos N, Gourtsoyiannis N.
Occupational radiation exposure from fluoroscopically guided percutaneoustranshepatic biliary procedures. J Vasc Interv Radiol 2006; 17(5), 863–871.
Thornton, R.H., Dauer, L.T., Altamirano, J.P., Alvarado, K.J., St. Germain, J., Solomon,
S.B., 2010. Comparing strategies for operator eye protection in the interventional
radiology suite. J. Vasc. Interv. Radiol. 21, 1703-1707.
Tsapaki V, Kottou S, Vano E, Komppa T, Padovani R, Dowling A, Molfetas M,
Neofotistou V. Occupational dose constraints in interventional cardiology
procedures: the DIMOND approach. Phys Med Biol. 2004 Mar 21;49(6):997-1005.
United Nations Scientific Committee on the Effects of Atomic Radiation. Sources andeffects of ionizing radiation. UNSCEAR 2000 report to the General Assembly, with
scientific annexes. Annex E. Occupational radiation exposures. (Available atwww.unscear.org). New York: United Nations; 2000.
Vano E, González L, Beneytez F, et al. Lens injuries induced by occupational exposurein non-optimised interventional radiology laboratories. Br J Radiol 1998a;71:728-33.
Vano E, Gonzalez L, Guibelalde E, et al. Radiation exposure to medical staff ininterventional and cardiac radiology. Br J Radiol 1998b;71:954-60.

77

DRAFT REPORT FOR CONSULTATION
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054

Vano E. Radiation exposure to cardiologists: how it could be reduced. Heart. 2003;
89(10):1123-4.
Vano E, Gonzalez L, Fernandez JM, Alfonso F, Macaya C. Occupational radiation
doses in interventional cardiology: a 15 year follow-up. Br J Radiol
2006;79(941):383-388.
Vano E, Gonzalez L, Fernandez JM, Prieto C, Guibelalde E. Influence of patient
thickness and operation modes on occupational and patient doses in interventional
cardiology. Radiat Prot Dosim 2006; 118(3): 325-330.
Vano E, Gonzalez L, Fernandez M, Haskal ZJ. Eye lens exposure to radiation ininterventional suites: caution is warranted. Radiology 2008; 248: 945-953.
Vano E, Kleiman NJ, Duran A, Rehani MM, Echeverri D, Cabrera. M. Radiation
cataract risk in interventional cardiology personnel. Radiat Res, 2010; 174(4):490495
von Boetticher H, Lachmund J, Hoffmann W. Cardiac catheterization: impact of faceand neck shielding on new estimates of effective dose. Health Phys 2009; 97(6),622– 627.
Wagner LK, Mulhern OR. Radiation-attenuating surgical gloves: effects of scatter andsecondary electron production. Radiology 1996; 200:45-48.
Wagner LK, Archer BR. Minimizing Risks from Fluoroscopic X-Rays: Bioeffects,
Instrumentation, and Examination. 4th Edition. The Woodlands, Texas:(Partners inRadiation Management, 2004.

78

DRAFT REPORT FOR CONSULTATION
3055
3056
3057
3058
3059
3060

Table 6.1.
Practical advice for interventionalists to improve staff radiation protection (from Vano etal, 2003 and Miller et al, 2010).

3061
3062
3063
3064



Increase your distance from the patient (the scatter radiation source) wheneverpossible. This is obviously only possible when angiographic runs are not performedby hand. Working at 80 cm from the isocenter instead of 40 cm can decrease scattereddose to approximately a quarter of the original dose.

3065
3066



Try to position yourself in a low scatter area. Scattered radiation is higher at the xray tube side of the gantry and lower on the side of the image receptor.

3067
3068



Use a ceiling suspended screen, a table-suspended screen and other protective
shielding, such as a lead apron, thyroid collar and lead glasses, when possible.

3069
3070



When appropriate, use a dose reduction pad or drape at the catheter entrance site to
reduce your hand dose.

3071
3072



Minimise the use of fluoroscopy and use low-dose fluoroscopy modes (for example,
pulsed fluoroscopy) when possible.

3073



Minimize the number of cine series and the number of frames per cine series.

3074



Use magnification as little as possible.

3075



Collimate the x-ray beam as tightly as possible.

3076



Obtain appropriate training in radiation management and radiation protection.

3077



Wear your dosimeters and know your own dose.

3078
3079
3080
3081



In addition, a final general concept: reduce the patient‘s radiation and you will also be
reducing your own dose.

79

DRAFT REPORT FOR CONSULTATION
3082
3083
3084

Table 6.2

3085

Integris 5000 fluoroscopy unit (Vano et al, 2006).

Relative increases in staff doses with changes in different operational features in a Philips

3086
ActionIncrease instaff dose

Changing from low to high fluoroscopy mode

× 2.6

(for a 20 cm thick patient)
Changing II format from 23 cm to 17 cm (for× 1.0

a 20 cm thick patient)
Changing patient thickness from 16 to 28 cm

× 4.2

Changing from low fluoroscopy mode to cine× 8.3

(for a 20 cm thick patient)
3087
3088
3089

80

DRAFT REPORT FOR CONSULTATION
3090
3091
3092
3093
3094

Table 6.3
Protection of different lead aprons for X-ray beams filtered with 3 mm Al and generated
at the kVp indicated (Vano et al, 2006).

kVp

Protective apron
Pb equivalent (mm)Fraction of energy transmitted (%)

90

0.25

8.3

90

0.35

4.9

90

0.50

2.4

80

0.25

5.7

80

0.35

3.0

80

0.50

1.3

70

0.25

3.3

70

0.35

1.5

70

0.50

0.5

3095
3096

81

DRAFT REPORT FOR CONSULTATION
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140

7. RADIOLOGICAL PROTECTION FOR NUCLEAR CARDIOLOGY
Main Points
 Appropriate use criteria and guidelines that help to set standards forjustification have been developed through consensus efforts of professionalsocieties.
 Optimization of nuclear cardiology procedures involves the judicious
selection of radiopharmaceuticals and administered activities to ensure
diagnostic image quality while minimizing patient dose.
 For SPECT protocols, Tc-99m-based agents yield lower effective doses thanTl-201, and are preferred on dosimetric grounds.
 Administered activities should be within pre-specified ranges, as provided ininternational and national guidelines, and should reflect patient habitus.
 If stress imaging is normal, rest imaging can be omitted to minimize totaldose.
 Practitioners need good quality dosimetry data to perform proper benefitrisk analyses for their patients.

7.1

Introduction(131) More than 90% of nuclear cardiology studies are myocardial perfusion
scintigraphy studies for the assessment of myocardial perfusion and/or viability. The vast
majority of nuclear cardiology procedures are performed with single photon emission
computed tomography (SPECT). A small but growing number of laboratories perform
positron emission tomography (PET) studies.
(132) An estimated 32.7 million diagnostic nuclear medicine procedures are
performed annually worldwide (UNSCEAR 2008). Of these, approximately 14 million
are nuclear cardiology procedures, and this number has increased rapidly (Davis, 2006).
More nuclear cardiology procedures are performed in the United States than in the rest of
the world combined. In the U.S., nuclear medicine procedures accounted for 26% of the
medical exposure of patients in 2006, and cardiac studies accounted for 85% of thenuclear medicine exposure (NCRP report 160, 2009).
7.2

Radiopharmaceuticals(133) The radiopharmaceuticals used most commonly for nuclear cardiology studies
are summarized in Table 7.1. In Europe, most studies are performed using Tc-99mbased agents, while in the United States, a sizable minority of studies are performed using
Tl-201, usually in the context of a dual isotope study with rest Tl-201 imaging followed
by stress Tc-99m imaging. The use of thallium results in a higher dose to the patient(Einstein et al, 2007).

82

DRAFT REPORT FOR CONSULTATION
3141

Table 7.1. Commonly Used Radiopharmaceuticals for Nuclear Cardiology
Role
Agent

(14)

(15)

erfusionP
unctionPhysicalF (16) V
Half-Lifeiability

ICRP
Publication

73h

106(2008)

-

6h

7.0

80(1998)

-

75s

3.4*

SPECT

+++

++

+

6h

Tc-99m tetrofosmin

SPECT

+++

++

+

6h

Tl-201

SPECT
Planar or
SPECT
MUGA

+++

+

++

-

+++

PET

+++

++

Rb-82

Effective Dose
(10-3 mSv/MBq)
9.0 rest/7.9
stress
7.6 rest/7.0
stress140

Tc-99m sestamibi

Tc-99m red blood
cells

3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172

Modality

80(1998)
80(1998)(17)

80(1998)*80(1998)

N-13 ammonia
PET
+++
++
10m
2.0
F-18
(18) 8
PET
+++
110m
19
fluorodeoxyglucose0(1998)SPECT: single photon emission computed tomography, PET: positron emission tomography: MUGA: multiple gatedacquisition* ICRP‘s dose coefficients for Rb-82, dating to Publication 53 (1987) and reiterated in Publication 80 (1998), reflect
for some organs ―worst case‖ conditions, as was stated in Publication 53, and thus dose estimates deriving therefrom
might be overly conservative. Three groups have recently suggested lower dose coefficients (Senthamizhchelvan et al
2010, 1.11 μSv/MBq; Hunter 2010, 0.74 μSv/MBq; and Stabin 2010, 1.7 μSv/MBq); the Commission is currently
revisiting the issue of Rb-82 dosimetry.

(134) Recommended administered activities for nuclear cardiology procedures vary
markedly among the professional societies and accrediting bodies in various countries(Hesse et al., 2005). Guidelines have been published by both the American Society of
Nuclear Cardiology (ASNC) (DePuey, 2006; Henzlova, 2009) and the European Council
on Nuclear Cardiology (ECNC) (Hesse et al., 2005), a joint group of the European
Association of Nuclear Medicine (EANM) and the European Society of Cardiology(ESC). Injected activity from these guidelines is summarized in Table 7.2.

83

DRAFT REPORT FOR CONSULTATION
3173
3174
3175
3176

3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197

Table 7.2. Recommended Injected Activity (MBq) for Standard Cardiac SPECT and PET
Protocols*740 to 925 for planar imaging**for 2 dimensional acquisition using camera with bismuth germanate or lutetiumoxyorthosilicate crystals
7.3

Dosimetry for nuclear cardiology(135) Two types of dose coefficients can be determined: 1) tissue dose coefficients,
which can be used to estimate the dose to a particular tissue or organ, and 2) effective
dose coefficients, which can be used to estimate effective dose to the individual. Notehowever that effective dose is intended for use as a radiological protection quantity.
Effective dose is not recommended for epidemiological evaluations, nor should it be used
for detailed specific retrospective investigations of individual exposure and risk (ICRP,
2007a).
(136) Estimates of organ dose and estimates of effective dose to patients are
generally obtained by using mathematical biokinetic models that quantify the distribution
and metabolism of a radiopharmaceutical in the body. These models incorporate
biokinetic data from humans and/or animals and enable the determination of dosecoefficients.
(137) Tissue dose coefficients quantify absorbed doses to a specific organ in a typicalpatient, per unit activity administered. For example, ICRP‘s current liver dose coefficient84DRAFT REPORT FOR CONSULTATION
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235

in an adult for the PET tracer F-18 fluorodeoxyglucose is 1.110-2 mGy per MBq (ICRP,
1998). Thus, a 200 MBq injection of F-18 fluorodeoxyglucose is associated with anestimated dose to the liver of 2.2 mGy.
(138) Effective dose coefficients quantify effective dose per unit activity
administered.
ICRP‘s current effective dose coefficient in an adult for F-18
fluorodeoxyglucose is 1.910-2 mSv per MBq (ICRP, 1998), and therefore the same 200
MBq injection of F-18 fluorodeoxyglucose would be associated with an estimatedeffective dose of 3.8 mSv.
(139) Several systems provide mathematical frameworks for estimating dosecoefficients, including those of ICRP Publication 30 (ICRP, 1979) and those of theSociety of Nuclear Medicine‘s Medical Internal Radiation Dose committee (Loevinger etal., 1988) and Radiation Dose Assessment Resource task group (Stabin et al., 2001).
These approaches are essentially equivalent (Stabin, 2006). They estimate radiation doseas energy per unit mass. Energy is generally determined from biokinetic models of theradiopharmaceutical‘s time-activity curve, from tables of the mean energy per nuclear
transition, and from Monte Carlo computer models. Organ masses are determined from amodel of a representative person.
(140) There are numerous collections of dose coefficients for specificradiopharmaceuticals. The most extensive compilations are those of the Commission, forwhich current estimates can be found in Publications 53 (ICRP, 1987), 80 (ICRP, 1998),
and 106 (ICRP, 2008). Effective doses for commonly used radiopharmaceuticals fornuclear cardiology, based on the most recent ICRP effective dose coefficients for theseradiopharmaceuticals, are listed in Table 7.1. These effective doses reflect ICRP
Publication 60 tissue weighting factors; updated effective dose coefficients reflecting
Publication 103 tissue weighting factors will be included in a forthcoming ICRP
publication. In many countries there is a regulatory requirement that dose coefficients beprovided in manufacturers‘ package inserts/product information (PI) sheets forradiopharmaceuticals.
7.4

Current dosimetry estimates(141) The dose to a typical patient from a nuclear cardiology study can be estimatedby multiplying dose coefficients by the administered activity. These estimates areillustrated in Figure 7.1, using the most recent ICRP dose coefficients for each agent andadministered activities in the middle of the range specified in Table 7.2.

85

DRAFT REPORT FOR CONSULTATION

3236

3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252

Figure 7.1. Effective doses from standard nuclear cardiology procedures, estimated using the most recent
ICRP dose coefficients and Publication 103 tissue weighting factors (ICRP, 2007a). Stacked bars represent
organ weighted equivalent doses contributing to effective dose. Doses for Tc-99m represent the average ofTc-99m sestamibi and tetrofosmin. Top: Using average recommended administered activities from
American Society of Nuclear Cardiology guidelines (Henzlova, 2009; DePuey, 2006). Bottom: Using
average recommended administered activities from European Council on Nuclear Cardiology guidelines(Hesse et al., 2005).
*Note that ICRP‘s dose coefficients for Rb-82, dating to Publication 53 (1987) and reiterated in Publication
80 (1998), reflect for some organs ―worst case‖ conditions, as was stated in Publication 53, and thus dose
estimates derived therefrom might be overly conservative. Three groups have recently suggested lower
dose coefficients (Senthamizhchelvan et al 2010, 1.11 μSv/MBq; Hunter 2010, 0.74 μSv/MBq; and Stabin
2010, 1.7 μSv/MBq); the Commission is currently revisiting the issue of Rb-82 dosimetry.

86

DRAFT REPORT FOR CONSULTATION
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295

7.5

Uncertainty in dosimetry(142) Because many terms are estimated and multiplied together to determine dosecoefficients, there are numerous potential sources of uncertainty in these dose estimates.
Differences between planned and actual administered activity are considered to be minor
contributors to the total uncertainty, if regular quality control is performed (ICRP, 1987).
The three most sizable contributors to uncertainty are inter-individual variability in organ
masses, absorbed fractions, and total activity in each organ. Uncertainties in organ
activity reflect differences in biokinetics. (Stabin, 2008b) Experimental validation of
calculated absorbed doses has indicated agreement within 20% to 60%, with the larger
value applicable to patients who differed considerably from the body size and shapeassumed in the calculations (Roedler, 1981). More recent publications contend that the
combined uncertainties for any given dose estimate of a radiopharmaceutical are
generally at least a factor of 2 (Stabin, 2008b).
7.6

Discrepancies between ICRP dosimetry and information frommanufacturers(143) The most readily available source of dosimetric data about aradiopharmaceutical is typically the information provided by the manufacturer. In
several cases, dose coefficients vary considerably between those given in ICRP
publications and those provided by manufacturers. These discrepancies may affect the
choice of diagnostic tests and the choice of radiopharmaceuticals, since radiation risk is
one factor that should be incorporated into benefit-risk analyses.
(144) One recent report evaluating package inserts in the United States found that
effective doses for Tl-201 estimated from a single manufacturer‘s information were lessthan half of those estimated from ICRP tables, while doses estimated from package
inserts from two other manufacturers were greater than or similar to ICRP effective
doses.(Einstein et al., 2007) These discrepancies are due, in part, to the numerous
sources of uncertainty incorporated into dose coefficients. However, they may also be
due to the use of limited and older data by manufacturers (Gerber et al., 2009; Stabin,
2008a).
(145) The Commission recommends that national regulatory authorities implement
programs to ensure the quality of dosimetric data in package inserts and productinformation. Aspects of quality include inclusion of effective dose coefficients (asopposed to total body dose coefficients), periodic post-approval updates to reflect theavailable dosimetric data, and transparency in the data sources and sample sizes used toobtain dose coefficients.
7.7

Radiological protection of patients in nuclear cardiology

87

DRAFT REPORT FOR CONSULTATION
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339

(146) The general principles of radiological protection (chapter 4), i.e. justificationand optimisation, can be applied to the protection of patients in nuclear cardiology. Doselimitation is not appropriate, but diagnostic reference levels should be used to help
manage the radiation dose so that the dose is commensurate with the clinical purpose(ICRP, 1977, ICRP, 2007a, ICRP, 2007b).
7.7.1 Justification(147) Nuclear cardiology studies should always be justified on clinical grounds(Gerber et al., 2009). Even in highly expert institutions, sizable percentages of nuclear
cardiology studies performed may not meet standardized criteria for appropriateness. To
a certain degree this may reflect limitations with appropriateness criteria, which may notincorporate all the information included in decision making for a particular patient.
However, in a recent retrospective analysis of 284 patients undergoing nuclear stresstesting at the Mayo Clinic, 25% had inappropriate or uncertain indications (Gibbons etal., 2008). Four inappropriate indications accounted for 88% of inappropriate studies.
The most common inappropriate indication was stress testing in an asymptomatic lowrisk patient.
(148) Pre-test classification of patients by indication, with a requirement for specificjustification for patients with no identified appropriate indication, offers an approach todecrease the number of nuclear stress tests performed that are not justified. The
Commission encourages the development and validation of national and regional
appropriateness criteria for utilization of cardiac imaging. For clinical scenarios in whichmore than one imaging modality might be used, appropriateness criteria should
simultaneously address these multiple modalities. (ACR, 2010). Alternative techniques(such as stress-echocardiography) are available, and should be considered wheneverpossible.
7.7.2 Optimization(149) Several methods can be used to control patient dose in nuclear cardiology.
These include choosing the most appropriate radiopharmaceutical(s), optimizing injected
activity, avoiding rest imaging when stress imaging is normal and encouraging hydrationand early micturition after radiopharmaceutical administration. Hydration and early
micturition may halve the dose to the bladder wall (Einstein et al., 2007).
(150) The choice of protocols is particularly critical. As illustrated in Table 2 andFigure 1, a variety of standard protocols are available for the performance of myocardial
perfusion imaging. Their effective doses can range from 2 mSv to nearly 30 mSv. The
lowest dose myocardial perfusion imaging protocols use N-13 ammonia. N-13 ammonia
is a PET tracer that requires an on-site cyclotron due to its 10-minute half-life. This
limits its availability.
(151) SPECT protocols may require one or two injections of a radiopharmaceutical.
The radiopharmaceutical may be Tl-201, a Tc-99m-based agent (sestamibi or
tetrofosmin), or both. The effective dose depends on the radiopharmaceutical(s) and88

DRAFT REPORT FOR CONSULTATION
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383

injected activities selected. In general, Tc-99m is preferable to Tl-201 on dosimetricgrounds. Effective doses are typically considerably higher for protocols using Tl-201,
and lowest for stress-only Tc-99m protocols. A protocol employing Tl-201 may be
optimal for some patients, e.g. those with a history of Tc-99m images obscured byincreased sub-diaphragmatic tracer uptake, if an alternative imaging modality is not used.
For patients with a low- or low-intermediate pre-test probability of a perfusion defect, inwhom it is expected that stress imaging will be normal, a stress-first/stress-only protocol
is recommended, since rest imaging can be omitted if stress images are normal (Hesse etal., 2005; Mahmarian, 2010). This approach may be especially useful in conjunction withattenuation correction, which decreases the percentage of studies with perfusion defects
due to artefact (Gibson et al., 2002).
(152) The Commission recommends formal training in radiological protection, and inparticular in the application of methods to minimize patient dose in accordance with
ALARA principles, for all physicians involved in nuclear cardiology studies, regardlessof their medical specialty. The recommended training is described in ICRP Publication
113 (ICRP, 2009). Additional recommendations are available from the IAEA (IAEA,
2001).
7.7.3 Diagnostic Reference Levels in Nuclear Cardiology(153) Diagnostic reference levels are used in medical imaging to indicate whether, inroutine conditions, the levels of patient dose from, or administered activity for, aspecified imaging procedure are unusually high or low for that procedure (ICRP, 2007a).
They are discussed further in Chapter 10. If so, a local review should be initiated todetermine whether protection has been adequately optimised or whether corrective action
is required.
(154) Professional medical bodies (in conjunction with national health andradiological protection authorities) are encouraged to set diagnostic reference levels thatbest meet their specific needs and that are consistent for the regional, national, or local
area to which they apply (ICRP, 2007b). In nuclear medicine, reference levels usually
have been derived from pragmatic values of administered activity based on accepted
custom and practice (ICRP, 2007b). Sources of diagnostic reference levels for nuclear
cardiology include ASNC, ECNC, and national guidelines, which provide a range ofadministered activities for each protocol. The activity administered to a given patient canbe adjusted within these ranges to reflect patient habitus. For example, while up to 1332
MBq of technetium-99m is recommended per injection in a two-day protocol, this upper
limit should be restricted to larger patients.
7.8

Advice to patients(155) In recent years, the threat of nuclear terrorism has led to the widespread use ofradiation detectors for security screening at airports and other public facilities. Patients
who have received radiopharmaceuticals for nuclear cardiology studies may retain
sufficient activity to trigger these detectors (Dauer, 2007b). In particular, patients who

89

DRAFT REPORT FOR CONSULTATION
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427

have received Tl-201 may trigger these detectors for up to 51 days following theprocedure (Dauer, 2007a). Patients should be advised of this possibility and should begiven information cards that indicate the potential time for triggering security radiation
detectors after diagnostic cardiac procedures involving the use of Tl-201 or otherradiopharmaceuticals (Dauer, 2007a)
7.9

Current research areas(156) Recent technological developments in nuclear cardiology, such as moresophisticated noise-reducing image reconstruction algorithms and new camera designs
that employ arrays of solid-state detectors, offer the possibility to improve camera
efficiency. Research efforts using these technologies have largely focused on decreasingacquisition time and improving image quality. These technologies also offer the potential
to markedly decrease administered activity and thereby patient dose, while maintaining
comparable diagnostic performance in comparison to conventional scanners. Further
investigation and clinical validation is required (Patton et al., 2007).
7.10

References

ACR, 2010. American College of Radiology ACR Appropriateness Criteria®. Clinical
Condition: Chronic Chest Pain — High Probability of Coronary Artery Disease.
Availableat:
http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria.aspx
Accessed January 2, 2011.
Dauer LT, Williamson MJ, St. Germain J, Strauss HW, 2007a. Tl-201 stress tests andhomeland security. J Nucl Cardiol 14(4):582-588.
Dauer LT, Williamson MJ, St. Germain J, Strauss HW, 2007b. Nuclear granny—reply.
J Nucl Cardiol 14(6):904-905.
Davis W. Mapping improvements in molecular imaging. Medical Imaging. 2006;May
2006. Available at: http://www.imagingeconomics.com/issues/articles/MI_200605_01.asp Accessed December 31, 2010.
DePuey, E.G., 2006. Imaging guidelines for nuclear cardiology procedures. 13, e21.
Earls, J.P., Berman, E.L., Urban, B.A., Curry, C.A., Lane, J.L., Jennings, R.S.,
McCulloch, C.C., Hsieh, J., Londt, J.H., 2008. Prospectively gated transverse
coronary CT angiography versus retrospectively gated helical technique: improved
image quality and reduced radiation dose. Radiology 246, 742-753.
Earls, J.P., Schrack, E.C., 2008. Prospectively gated low-dose CCTA: 24 months
experience in more than 2,000 clinical cases. Int J Cardiovasc Imaging.
Einstein, A.J., Moser, K.W., Thompson, R.C., Cerqueira, M.D., Henzlova, M.J., 2007.
Radiation dose to patients from cardiac diagnostic imaging. Circulation 116, 12901305.
Gerber, T.C., Carr, J.J., Arai, A.E., Dixon, R.L., Ferrari, V.A., Gomes, A.S., Heller,
G.V., McCollough, C.H., McNitt-Gray, M.F., Mettler, F.A., Mieres, J.H., Morin,
R.L., Yester, M.V., 2009. Ionizing Radiation in Cardiac Imaging. A Science90DRAFT REPORT FOR CONSULTATION
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470

Advisory from the American Heart Association Committee on Cardiac Imaging of
the Council on Clinical Cardiology and Committee on Cardiovascular Imaging andIntervention of the Council on Cardiovascular Radiology and Intervention.
Circulation 119, 1056-1065.
Gibbons, R.J., Miller, T.D., Hodge, D., Urban, L., Araoz, P.A., Pellikka, P., McCully,
R.B., 2008. Application of appropriateness criteria to stress single-photon emission
computed tomography sestamibi studies and stress echocardiograms in an academic
medical center. J Am Coll Cardiol 51, 1283-1289.
Gibson, P.B., Demus, D., Noto, R., Hudson, W., Johnson, L.L., 2002. Low event rate forstress-only perfusion imaging in patients evaluated for chest pain. J Am Coll Cardiol
39, 999-1004.
Gutstein, A., Wolak, A., Lee, C., Dey, D., Ohba, M., Suzuki, Y., Cheng, V., Gransar, H.,
Suzuki, S., Friedman, J., Thomson, L.E., Hayes, S., Pimentel, R., Paz, W., Slomka,
P., Berman, D.S., 2008. Predicting success of prospective and retrospective gatingwith dual-source coronary computed tomography angiography: development of
selection criteria and initial experience. Journal of Cardiovascular Computed
Tomography 2, 81-90.
Henzlova, M.J., Cerqueira, M.D., Hansen, C.L., Taillefer, R., Yao, S.-S., 2009. ASNC
imaging guidelines for nuclear cardiology procedures. Stress prorocols and tracers.
Availableat:
http://www.asnc.org/imageuploads/ImagingGuidelinesStressProtocols021109.pdf
Accessed January 2, 2011,
Hesse, B., Tagil, K., Cuocolo, A., Anagnostopoulos, C., Bardies, M., Bax, J., Bengel, F.,
Busemann Sokole, E., Davies, G., Dondi, M., Edenbrandt, L., Franken, P., Kjaer, A.,
Knuuti, J., Lassmann, M., Ljungberg, M., Marcassa, C., Marie, P.Y., McKiddie, F.,
O'Connor, M., Prvulovich, E., Underwood, R., van Eck-Smit, B., 2005. EANM/ESC
procedural guidelines for myocardial perfusion imaging in nuclear cardiology. Eur J
Nucl Med Mol Imaging 32, 855-897.
Hunter, C., Ziadi, M., Etele, J., Hill, J., Beanlands, R., deKemp, R., 2010. New effective
dose estimates for Rubidium-82 based on dynamic PET/CT imaging in humans. J
Nucl
Med.
2010;
51(Suppl
2):1429.
Availableat:
http://jnumedmtg.snmjournals.org/cgi/content/meeting_abstract/51/2_MeetingAbstra
cts/1429 Accessed January 2, 2011.
Husmann, L., Valenta, I., Gaemperli, O., Adda, O., Treyer, V., Wyss, C.A., VeitHaibach, P., Tatsugami, F., von Schulthess, G.K., Kaufmann, P.A., 2008. Feasibilityof low-dose coronary CT angiography: first experience with prospective ECGgating. Eur Heart J 29, 191-197.
IAEA, 2001. Training in radiation protection and the safe use of radiation sources.
Safety Report Series No. 20. Vienna: International Atomic Energy Agency, 2001.
ICRP, 1977. Recommendations of the International Commission on RadiologicalProtection. ICRP publication 26. Ann ICRP 1(3), 1-53.
ICRP, 1979. ICRP publication 30: limits for intakes of radionuclides by workers. Ann
ICRP 2, 1-116.

91

DRAFT REPORT FOR CONSULTATION
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513

ICRP, 1987. Radiation dose to patients from radiopharmaceuticals. A report of a Task
Group of Committee 2 of the International Commission on Radiological Protection.
ICRP Publication 53. Ann.ICRP 18, 1-29.
ICRP, 1998. Radiation dose to patients from radiopharmaceuticals (addendum 2 to ICRP
publication 53). ICRP Publication 80. Ann.ICRP 28, 1-123.
ICRP, 2001. Radiation dose to patients from radiopharmaceuticals. A report of a Task
Group of Committees 2 and 3 of the International Commission on RadiologicalProtection. Addendum 5 to ICRP Publication 53.
ICRP, 2007a. The 2007 recommendations of the International Commission on
Radiological Protection. ICRP Publication 103. Ann.ICRP 37, 1-332.
ICRP, 2007b. Radiological Protection in Medicine. ICRP Publication 105. Ann.ICRP
37(6), 1-64.
ICRP, 2008. Radiation dose to patients from radiopharmaceuticals. Addendum 3 to
ICRP Publication 53. ICRP Publication 106. Approved by the Commission in
October 2007. Ann ICRP 38, 1-197.
ICRP, 2009. Radiological protection education and training for healthcare staff andstudents (diagnostic imaging and interventional procedures). ICRP Publication 113.
Ann ICRP 39 (5).
Loevinger, R., Budinger, T., Watson, E., 1988. MIRD primer for absorbed dose
calculations. Society of Nuclear Medicine, New York.
Mahmarian, J.J., 2010. Stress only myocardial perfusion imaging: Is it time for achange? J Nucl Cardiol 17, 529-535.
National Council on Radiation Protection and Measurements. Ionizing radiation
exposure of the population of the United States. NCRP Report No. 160. Bethesda,
MD: National Council on Radiation Protection and Measurements; 2009.
Patton, J.A., Slomka, P.J., Germano, G., Berman, D.S., 2007. Recent technologic
advances in nuclear cardiology. J Nucl Cardiol 14, 501-513.
Roedler, H.D., 1981. Accuracy of internal dose calculations with special consideration ofradiopharmaceutical biokinetics, Third International Radiopharmaceutical Dosimetry
Symposium, HHS Publication FDA 81-8166. Department of Health and Human
Welfare, Bureau of Radiological Health, Rockville, MD.
Rybicki, F.J., Otero, H.J., Steigner, M.L., Vorobiof, G., Nallamshetty, L., Mitsouras, D.,
Ersoy, H., Mather, R.T., Judy, P.F., Cai, T., Coyner, K., Schultz, K., Whitmore,
A.G., Di Carli, M.F., 2008. Initial evaluation of coronary images from 320-detectorrow computed tomography. Int J Cardiovasc Imaging 24, 535-546.
Senthamizhchelvan, S., Bravo, P.E., Esaias, C., Lodge, M.A., Merrill, J., Hobbs, R.F.,
Sgouros, G., Bengel, F.M., 2010. Human biodistribution and radiation dosimetry of82
Rb. J. Nucl. Med. 51, 1592-1599.
Stabin, M., 2006. Nuclear medicine dosimetry. Phys Med Biol 51, R187-202.
Stabin, M., Siegel, J., Hunt, J., Sparks, R., Lipsztein, J., Eckerman, K., 2001. RADAR:
the radiation dose assessment resource—an online source of dose information for
nuclear medicine and occupational radiation safety [abstract]. J Nucl Med 42(suppl),
243P.

92

DRAFT REPORT FOR CONSULTATION
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526

Stabin, M.G., 2008a. Radiopharmaceuticals for nuclear cardiology: radiation dosimetry,
uncertainties, and risk. J Nucl Med 49, 1555-1563.
Stabin, M.G., 2008b. Uncertainties in internal dose calculations forradiopharmaceuticals. J Nucl Med 49, 853-860.
Stabin, M.G., 2010. Proposed revision to the radiation dosimetry of 82Rb. Health Phys.
99, 811-813.
UNSCEAR. Sources and effects of ionizing radiation: volume I, sources: annex D,
medical radiation exposure. Report to the General Assembly of the United Nations;
2000;
New
York,
NY
Availableat:
http://www.unscear.org/unscear/en/publications/2000_1.html Accessed December
31, 2010.

93

DRAFT REPORT FOR CONSULTATION
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570

8. RADIOLOGICAL PROTECTION FOR CARDIAC CT
Main Points
 Appropriate use criteria and guidelines for justification have been developed
through consensus efforts of professional societies.
 Justification needs to be performed on an individualized, patient-by-patientbasis, weighing the benefits and risks of each imaging test underconsideration as well as of doing no test. Assessment of radiation risk is one
part of this process.
 Dose from cardiac CT is strongly dependent on scanner mode, tube current,
and tube voltage.
 For patients with a heart rate less than 65-70 bpm and a regular rhythm,
diagnostic image quality can generally be maintained while using dosereduction methods such as ECG-controlled tube current modulation andaxial imaging. The maximum tube current should be appropriate for thepatient’s habitus.
 Further research is needed to develop and validate methods, such as newer
scan modes and low-voltage scanning, to minimize radiation dose to patientsand practitioners.
8.1

Introduction(157) The possibility of CT of the coronary arteries was suggested by Sir Godfrey
Hounsfield, inventor of the CT scanner, in his 1979 Nobel Lecture when he stated ―A
further promising field may be the detection of the coronary arteries. It may be possible
to detect these under special conditions of scanning.‖ (Hounsfield, 1979). Unlike nuclear
cardiology technology, which has remained largely static, cardiac CT technology has
evolved rapidly in recent years. These advancements have enabled a variety of types ofcardiac CT studies to be performed. Today, cardiac CT encompasses several distinct
procedures, including coronary artery calcium (CAC) scoring, CT coronary angiography(CTCA), pulmonary vein CT angiography, and CT attenuation correction of nuclear
cardiology image data. Recent technological advances have been associated with anincrease in the number of procedures performed, although reliable statistics on worldwide
numbers are not available at present.
8.2

Types of CT scanners(158) Each new generation of CT scanners has varied from its predecessors in termsof technical parameters (e.g., temporal resolution, spatial resolution, craniocaudal
coverage) and also in patent radiation dose. The first scanner capable of performing
cardiac studies, the dynamic spatial reconstructor, used 14 x-ray sources that rotatedaround the patient, resulting in patient doses approaching 100 Gy (Block et al., 1984).
The electron beam CT scanner, also called ―ultrafast‖ CT due to its excellent temporal
resolution, superseded this machine. Patient dose from electron beam CT was markedly
94

DRAFT REPORT FOR CONSULTATION
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614

lower, with typical effective doses of approximately 1 mSv for both CAC scoring and
CTCA (Morin et al., 2003). Electron beam CT scanners had low spatial resolution, andhave been supplanted by multiple-detector-row CT (MDCT) scanners. The improved
spatial resolution of MDCT scanners enables a more accurate assessment of coronary
stenosis and plaque visualization. Initial efforts at CTCA were performed with 4-slice
scanners. The technology gained popularity with subsequent generations of faster 16and 64-slice scanners and became even more widespread with the advent of 128- and256-slice scanners. MDCT is the focus of ICRP Publication 102 (ICRP, 2007a).
8.3

Dosimetric Quantities(159) Currently, three types of dosimetric quantities are utilized for CT. These are: i)weighted CT dose index (CTDIw) and volume CT dose index (CTDIvol), ii) dose-length
product (DLP), and iii) effective dose. CTDIw and CTDIvol are estimates of the average
dose within the central portion of the scan volume. DLP integrates the CTDIvol over thelength of the anatomy scanned, and reflects the increased patient dose when a longer
portion of the patient is scanned (e.g., chest vs. heart). Effective dose is a calculated
quantity used to reflect the risk of a radiation exposure to a portion of the body in termsof a uniform whole-body exposure. Effective dose was developed as a radiologicalprotection quantity, and is used to compare radiation risk among different diagnostic
examinations (ICRP, 2007b; McCollough, 2008)(160) Current MDCT scanners typically report CTDIvol and DLP for each study.
Effective dose can be estimated by multiplying DLP by a body-region-specificconversion factor (k factor). For cardiac studies, the most commonly used conversion
factor is of 0.017 mSv·mGy-1·cm-1, the European Guidelines on Quality Criteria for
Computed Tomography chest factor (i.e., effective dose is estimated as 0.017·DLP)(Bongartz et al., 2000). This conversion factor does not reflect the more recent ICRP
Publication 103 tissue weighting factors, is derived from data from single-slice scanners,
and was developed for chest scans rather than cardiac scans (Christner et al., 2010;
Einstein et al., 2010). This method provides a useful approximation of effective dosefrom cardiac CT based on easily available data, but it typically underestimates effective
dose. Alternative, more complex approaches for determining effective dose are Monte
Carlo simulations and determination of organ doses in physical anthropomorphic
phantoms. These are discussed in more detail in ICRP Publication 102 (ICRP, 2007a).
8.4

Factors affecting patient dose(161) Factors affecting patient dose in cardiac CT include both those intrinsic to thescanner, such as scanner generation, model and manufacturer, and parameters selected by
the operator. Hausleiter et al, in an observational study of 50 sites performing CTCA,
observed a marked difference between scanner manufacturers in effective dose
(Hausleiter et al., 2009). Reported doses from CTCA vary depending on which
generation of MDCT scanners was used (Einstein et al., 2007). The most recent
generation of scanners incorporates technology with the potential to decrease patient95

DRAFT REPORT FOR CONSULTATION
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643

doses considerably. Operator-selectable parameters that affect dose include x-ray tube
current (mA) or tube current-time product (mAs), tube peak voltage (kVp), pitch (IEC,
2009), scan length (craniocaudal coverage), scan mode, and in some cases the number of
x-ray tubes employed.
8.4.1 Tube Current(162) The choice of an appropriate mA and kVp for a given study reflects a trade-off
between image noise and radiation dose. Increasing the tube current results in both adecrease in image noise and an increase in radiation dose. Dose increases in a roughly
linear fashion with increased tube current (Gerber et al., 2005). Baseline tube current
should be adjusted to reflect patient habitus, as larger patients will require a higher tube
current to obtain images with standard levels of noise. For the same tube current,
different scanners will produce images with different amounts of noise, so protocols must
be tailored to each scanner. A sensible balance is required—overly aggressive reductions
in radiation dose may render the scan non-diagnostic. New image reconstruction
algorithms incorporating an iterative noise-reduction methodology may maintain image
quality while decreasing tube current.
8.4.2 Tube Voltage(163) For cardiac MDCT applications, a tube voltage of 120 kVp is common. For
smaller patients, a lower voltage, e.g. 100 kVp, is used in some centres. Dose varies
approximately with voltage to the 2.5 power, so a 37% dose reduction would be expectedwith this decrease in tube voltage. The evidence supporting low-voltage CTCA (Abadaet al., 2006; Bischoff et al., 2009; Hausleiter et al., 2010) is not as robust as that
supporting 120 kVp CTCA (Abdulla et al., 2007). However, many sites have obtained
excellent image quality using reduced voltage (Figure 8.1).

96

DRAFT REPORT FOR CONSULTATION

3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664

Figure 8.1. CT coronary angiogram, obtained using a tube voltage of 100 kVp andsingle-heartbeat volume scanning. Courtesy Andrew J. Einstein, MD, PhD, Columbia
University Medical Centre, New York, NY, USA
8.4.3 Scan Length(164) Patient dose is linearly related to the length of the portion of the body
irradiated, which is basically equal to the scan length. Typically CTCA is performed
with scanning from the carina to the base of the heart, with a small margin of error oneach side to allow for patient motion. A scan length of 11-15 cm is typical. Excessively
large margins result in increased patient dose without additional diagnostic information.
Greater craniocaudal coverage is necessary when the aorta must be included and in cases
where the patient has undergone coronary artery bypass grafting, in which case the upper
limit of the scan is above the aortic arch. For pulmonary vein CT angiography, the scan
length can be reduced. In this case the structures of interest are the left atrium,
pulmonary veins, and their anatomic relationship to the oesophagus and aorta; these canbe visualized without scanning caudally to the cardiac apex.
8.4.4 Scan Mode

97

DRAFT REPORT FOR CONSULTATION
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708

(165) Scan modes include conventional helical (spiral) imaging with constant tube
current, conventional helical imaging with ECG-gated tube current modulation(EGTCM), high-pitch helical imaging and axial imaging, including both step-and-shootand volume imaging (Figure 8.2). CTCA using MDCT was first performed using helicalmode and a constant tube current, with a typical pitch of 0.2 for 64-slice scanners(Figure. 8.2 (a)). All current cardiac scanners offer EGTCM, which keeps tube current
at its maximum during diastasis, when coronary movement is generally minimized, anddecreases tube current during the remainder of the cardiac cycle (Figure 8.2 (b)). This
limits the number of phases of the cardiac cycle in which image reconstructions can be
performed without excessive noise, but for patients with low heart rates (<65 bpm) andregular heart rhythms, this generally does not pose a problem. Generally, patients should
receive beta blockers or calcium channel blockers to lower heart rate and improve theefficacy of EGTCM. For patients who do not meet these conditions, reconstructions at
end-systole are often quite useful for visualizing the proximal- and mid-right coronary
artery (Sanz et al., 2005). If EGTCM is applied in these patients, it may be advisable towiden the period of time during which tube current is maintained at its maximal value.
EGTCM typically decreases effective dose by about one-third. For single-source
scanners, this decrease in dose is more pronounced with lower heart rates (Jakobs et al.,2002).
(166) More recently, axial CTCA protocols have been incorporated into some MDCT
scanners. This approach to scanning acquires image data only during a pre-specified
phase of the cardiac cycle, and the x-ray beam is off during the remainder of the cardiac
cycle. In step-and-shoot (sequential) scanning, x-rays are delivered in one cardiac cycle,
the patient couch is advanced with the beam off during the next cardiac cycle, and theprocess is repeated until the entire craniocaudal volume of interest has been scanned. For
64-detector-row scanners, this generally requires 3 or 4 iterations, i.e. 5 or 7 heartbeats (5heartbeats illustrated in Figure 8.2 (c)). For step-and-shoot imaging to generateinterpretable cardiac images, it is generally thought that heart rate should be less than 70
beats per minute and heart rhythm should be regular, although this has not been wellstudied. An advantage of step-and-shoot imaging is reduced dose due to the eliminationof radiation exposure during much of the cardiac cycle and the absence of the overlap ofirradiated areas characteristic of helical CTCA. Disadvantages include the inability toretrospectively perform image reconstruction at additional phases of the cardiac cycle andthe attendant inability to assess cardiac function and wall motion.
(167) One modification of axial imaging is to increase the length of time that the xray tube is on, thus increasing dose but enabling reconstructions within a range of phasesof the cardiac cycle (Figure 8.2 (d)). Thus, rather than obtaining only images in a single
portion of diastasis, a variety of strategies can be employed, such as obtaining images in arange of diastolic phases, or covering from end-systole through diastasis. Dose is
proportional to exposure time. The optimal strategy for implementation of axial imaging
has not yet been determined.
(168) Two recently-introduced scan modes offer the potential for significant dose
reductions. Both cover the entire heart with x-rays delivered for only a fraction of asingle heartbeat (Figure 8.2 (e)). The extreme case of axial imaging is volume scanning,98DRAFT REPORT FOR CONSULTATION
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721

3722
3723
3724

which uses a cone-beam x-ray source and a large detector array that covers the entire
heart without requiring table motion (Einstein et al., 2010). The extreme case of helicalimaging is high-pitch helical scanning, in which two x-ray sources mounted at 90° fromeach other are used with a rapid table speed to enable the entire heart to be covered in a
fraction of a beat.(Achenbach et al., 2010) Each of these modes currently requires a low
heart rate to obtain excellent image quality at minimal radiation dose.
(169) The clinical literature evaluating axial CTCA and the single-heartbeat modes islimited (Earls et al., 2008; Gutstein et al., 2008; Husmann et al., 2008; Rybicki et al.,2008). There are no multicentre studies evaluating diagnostic accuracy efficacy incomparison to gold-standard diagnosis by invasive angiography. These scan modes
require more rigorous validation.
Figure 8.2

Scan modes used in cardiac CT. Black line denotes electrocardiographic signal, shaded
region represents tube current. (a) helical scan, (b) helical scan with99

DRAFT REPORT FOR CONSULTATION
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768

electrocardiographically-gated tube current modulation, (c) axial step-and-shoot scan, (d)axial step-and-shoot scan, with extending exposure time (―padding‖) to permit
reconstruction of multiple cardiac phases, (e) axial single heartbeat scan (volume andhigh-pitch helical scans, illustrated here with no padding). Not all modes are available on
all MDCT scanners.
8.5

Current Dosimetry Estimates(170) Dosimetry from CTCA depends on many factors, and thus varies markedly
between protocols. Einstein et al reviewed the published literature on effective dose fromcardiac CT in 2007(Einstein et al., 2007). Effective doses from calcium scoring ranged
from 1.0 to 6.2 mSv using helical technique and from 0.5 to 1.8 mSv using axial
technique. For helical 64-slice CTCA, effective dose ranged from 8 to 21.4 mSv without
and from 6.4 to 14 mSv with EGTCM. In a 15 centre study performed in the U.S.,
median effective dose, estimated using a k factor of 0.014 mSv·mGy-1·cm-1, was 21 mSv
prior to a best-practice dose reduction educational intervention (Raff et al., 2009). In a
50-centre worldwide study, median effective dose was 12 mSv (Hausleiter et al., 2009).
In Hausleiter et al‘s study, there was a 6-fold range in median doses among sites
performing CTCA. EGTCM was associated with a reduction in dose-length product andeffective dose of 25% (95% confidence interval 23-28%), use of an x-ray tube voltage of
100 kV was associated with a reduction of 46% (95% confidence interval 42-51%), anduse of axial step-and-shoot scanning was associated with a reduction of 78% (95%
confidence interval 77-79%) (Hausleiter et al., 2009). Other single-centre studies haveevaluated axial step-and-shoot scanning, and typically report effective doses in the 2-4
mSv range (Earls and Schrack, 2008). In comparison to conventional helical scanning,volume scanning has been associated with a dose reduction of 84%, (Einstein et al.,2010), and high-pitch helical scanning has been associated with effective dose of <1 mSv
for patients with a slow (≤60 bpm) heart rate who weigh ≤100 kg (Achenbach et al.,2010), using a k factor of 0.014 mSv·mGy-1·cm-1.
(171) The wide range of values for effective dose seen in clinical practice makes it
impossible to provide ―typical‖ values for cardiac CT. Effective dose is dependent on
both the CT scanner and the protocol used. Estimates of approximate average values arepresented in Table 8.1, but it must be appreciated that these values should not be
considered as typical values, target values, or representative of clinical practice at any
one institution.

100

DRAFT REPORT FOR CONSULTATION
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811

Table 8.1 Estimated Approximate Average Effective Dose for Various Types of Cardiac
CT Examinations
Examination

Effective Dose (mSv)*

CT coronary angiography (CTCA) (helical)

19

CT coronary angiography (CTCA) (tube current modulation)

13

CT coronary angiography (CTCA) (prospectively gated)

4

Coronary artery calcium scoring (CAC)

2*The data in the Table are reproduced from Einstein, 2009. For other estimates ofeffective dose, see, e.g., Einstein et al, 2007; Hausleiter et al, 2009; Kim et al, 2009;
Smith-Bindman et al, 2009; Earls and Schrack, 2009; Raff et al, 2009.

(172) Effective doses reported in many of the studies assessing CT protocols are
determined on a patient-by-patient basis. The existence of conversion factors, such as
those in the European Guidelines on Quality Criteria for CT (Bongartz et al., 2000;
Bongartz et al.), make it easy for an investigator to estimate an ―effective dose‖ for asingle study from the DLP reported on the scanner, but this is not the intended use ofeffective dose (Einstein et al., 2008; Gerber et al., 2009; ICRP 2007b). Citation of thesestudies is not an endorsement of this approach by the Commission. When theCommission introduced effective dose in 1990 (ICRP, 1991), it was defined for
populations, not for specific individuals. This has not changed.
8.6

Radiological Protection of Patients in Cardiac CT(173) The general principles of radiological protection (chapter 4), i.e., justificationand optimisation, can be applied to the protection of patients in cardiac CT. Doselimitation is not appropriate, but diagnostic reference levels should be used to help
manage the radiation dose so that the dose is commensurate with the clinical purpose(ICRP, 2007b, ICRP, 2007c).
8.6.1 Justification(174) The Commission recommends the development and application of appropriate
use criteria for cardiac CT. Appropriate indications for cardiac CT are available fromprofessional organizations and should be used (Taylor et al, 2010; Schroeder et al., 2008).

101

DRAFT REPORT FOR CONSULTATION
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855

(175) In reports from one institution, 46% of CTCA studies but only 11% of stress
SPECT studies were unclassifiable in terms of appropriateness, and of the remainingclassifiable studies, 51% of CTCA studies and 72% of stress SPECT studies wereappropriate.(Gibbons et al., 2008; Miller et al.) It is unclear from these data whether thedifference between modalities primarily reflects a limitation with the first version of the
U.S. CTCA appropriateness criteria, which left many studies unclassifiable, or whether
CTCA studies are less likely to be performed for appropriate indications that SPECT
studies. Further investigation is required, and programs to ensure maximal adherence toappropriate use criteria are also encouraged.
8.6.2 Optimization(176) As discussed in section 8.3, the operator controls numerous scan parametersthat affect patient dose. The operator should be provided with appropriate guidelines for
mAs and kVp selection as a function of patient body habitus. Special consideration
should be given to reducing mAs and/or kVp when evaluation of coronary plaques andstenoses is not the primary aim, e.g. for evaluation of possible anomalous coronaries, orprior to repeat cardiac surgery to assess the course of bypass grafts in relation to thesternum. Scan length should be limited to that needed to reliably image the volume ofinterest.
(177) The operator should be provided with appropriate guidelines for selection of
the scan mode. Scan modes that reduce dose should be employed as appropriate (Gerber
et al., 2009). Scans performed for calcium scoring should be performed using axial
imaging, and in combined studies should be reviewed prior to performance of CTCA.
The presence of widespread, heavy coronary calcification may suggest that CTCA should
not be performed, due to the high likelihood of unevaluable coronary segments. For all
patients, with the possible exception of patients scanned on a multiple-source scannerwith variable pitch, rate-control agents should be given as needed with the goal of
decreasing heart rate to approximately 60 beats per minute.
(178) The Commission recommends formal training in radiological protection, and inparticular in the application of the principles of justification and optimization, for all
physicians who refer patients for, or perform, cardiac CT studies (ICRP 113, 2011). This
includes cardiologists, radiologists, nuclear medicine specialists, and internists.
(179) Quality improvement programs have been shown to decrease radiation dose
substantially for CTCA (Raff et al., 2009), and thus their implementation is encouraged.
8.6.3 Diagnostic Reference Levels(180) Diagnostic reference levels are used in medical imaging to indicate whether, inroutine conditions, the levels of patient dose from, or administered activity for, aspecified imaging procedure are unusually high or low for that procedure (ICRP, 2007b).
They are discussed further in Chapter 10. If so, a local review should be initiated todetermine whether protection has been adequately optimised or whether corrective action
is required.

102

DRAFT REPORT FOR CONSULTATION
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899

(181) Professional medical bodies (in conjunction with national health andradiological protection authorities) are encouraged to set diagnostic reference levels thatbest meet their specific needs and that are consistent for the regional, national, or local
area to which they apply (ICRP, 2007c). At present, no diagnostic reference levels exist
for cardiac CT.
8.7

References

Abada, H.T., Larchez, C., Daoud, B., Sigal-Cinqualbre, A., Paul, J.F., 2006. MDCT ofthe coronary arteries: feasibility of low-dose CT with ECG-pulsed tube current
modulation to reduce radiation dose. AJR Am J Roentgenol 186, S387-390.
Abdulla, J., Abildstrom, S.Z., Gotzsche, O., Christensen, E., Kober, L., Torp-Pedersen,C., 2007. 64-multislice detector computed tomography coronary angiography as
potential alternative to conventional coronary angiography: a systematic review andmeta-analysis. Eur Heart J 28, 3042-3050.
Achenbach, S., Marwan, M., Ropers, D., Schepis, T., Pflederer, T., Anders, K., Kuettner,
A., Daniel, W.G., Uder, M., Lell, M.M., 2010. Coronary computed tomography
angiography with a consistent dose below 1 mSv using prospectively
electrocardiogram-triggered high-pitch spiral acquisition. Eur Heart J 31, 340-346.
Bischoff, B., Hein, F., Meyer, T., Hadamitzky, M., Martinoff, S., Schomig, A.,
Hausleiter, J., 2009. Impact of a reduced tube voltage on CT angiography andradiation dose: results of the PROTECTION I study. JACC Cardiovasc Imaging 2,940-946.
Block, M., Bove, A.A., Ritman, E.L., 1984. Coronary angiographic examination with the
dynamic spatial reconstructor. Circulation 70, 209-216.
Bongartz, G., Golding, S.J., Jurik, A.G., Leonardi, M., van Meerten, E.v.P., Geleijns, J.,
Jessen, K.A., Panzer, W., Shrimpton, P.C., Tosi, G., 2000. European Guidelines on
Quality Criteria for Computed Tomography. EUR 16262. The European
Commission's Study Group on Development of Quality Criteria for Computed
Tomography.
Bongartz, G., Golding, S.J., Jurik, A.G., Leonardi, M., van Meerten, E.v.P., Rodríguez,
R., Schneider, K., Calzado, A., Geleijns, J., Jessen, K.A., Panzer, W., Shrimpton,
P.C., Tosi, G., 2004 CT Quality Criteria, European Commission.
Christner, J.A., Kofler, J.M., McCollough, C.H., 2010. Estimating effective dose for CT
using dose-length product compared with using organ doses: consequences ofadopting International Commission on Radiological Protection publication 103 ordual-energy scanning. AJR Am J Roentgenol 194, 881-889.
Earls, J.P., Schrack, E.C., 2009. Prospectively gated low-dose CCTA: 24 months
experience in more than 2,000 clinical cases. Int. J. Cardiovasc. Imaging 25, 177187.
Einstein, A.J., Elliston, C.D., Arai, A.E., Chen, M.Y., Mather, R., Pearson, G.D.N.,
DeLaPaz, R.L., Nickoloff, E., Dutta, A., Brenner, D.J., 2010. Radiation dose fromsingle heartbeat coronary CT angiography performed using a 320 detector-row
volume scanner. Radiology 254, 698-704.

103

DRAFT REPORT FOR CONSULTATION
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943

Einstein, A.J., 2009. Medical imaging: the radiation issue. Nat. Rev. Cardiol. 6, 436-438.
Einstein, A.J., Moser, K.W., Thompson, R.C., Cerqueira, M.D., Henzlova, M.J., 2007.
Radiation dose to patients from cardiac diagnostic imaging. Circulation 116, 12901305.
Einstein, A.J., Sanz, J., Dellegrottaglie, S., Milite, M., Sirol, M., Henzlova, M.,
Rajagopalan, S., 2008. Radiation dose and cancer risk estimates in 16-slice computed
tomography coronary angiography. J Nucl Cardiol 15, 232-240.
Gerber, T.C., Carr, J.J., Arai, A.E., Dixon, R.L., Ferrari, V.A., Gomes, A.S., Heller,
G.V., McCollough, C.H., McNitt-Gray, M.F., Mettler, F.A., Mieres, J.H., Morin,
R.L., Yester, M.V., 2009. Ionizing Radiation in Cardiac Imaging. A Science
Advisory From the American Heart Association Committee on Cardiac Imaging of
the Council on Clinical Cardiology and Committee on Cardiovascular Imaging andIntervention of the Council on Cardiovascular Radiology and Intervention.
Circulation 119, 1056-1065.
Gerber, T.C., Stratmann, B.P., Kuzo, R.S., Kantor, B., Morin, R.L., 2005. Effect ofacquisition technique on radiation dose and image quality in multidetector row
computed tomography coronary angiography with submillimeter collimation.
Invest.Radiol. 40, 556.
Gibbons, R.J., Miller, T.D., Hodge, D., Urban, L., Araoz, P.A., Pellikka, P., McCully,
R.B., 2008. Application of appropriateness criteria to stress single-photon emission
computed tomography sestamibi studies and stress echocardiograms in an academic
medical center. J Am Coll Cardiol 51, 1283-1289.
Hausleiter, J., Meyer, T., Hadamitzky, M., Huber, E., Zankl, M., Martinoff, S., Kastrati,A., Schomig, A., 2006. Radiation dose estimates from cardiac multislice computed
tomography in daily practice: impact of different scanning protocols on effective
dose estimates. Circulation 113, 1305.
Hausleiter, J., Meyer, T., Hermann, F., Hadamitzky, M., Krebs, M., Gerber, T.C.,
McCollough, C., Martinoff, S., Kastrati, A., Schömig, A., Achenbach, S., 2009.
Estimated radiation dose associated with cardiac CT angiography. JAMA 301, 500507.
Hausleiter, J., Martinoff, S., Hadamitzky, M., Martuscelli, E., Pschierer, I., Feuchtner,
G.M., Catalan-Sanz, P., Czermak, B., Meyer, T.S., Hein, F., Bischoff, B., Kuse, M.,
Schomig, A., Achenbach, S., 2010. Image quality and radiation exposure with a low
tube voltage protocol for coronary CT angiography. Results of the PROTECTION II
Trial. JACC Cardiovasc Imaging 3, 1113-1123.
Hounsfield, G.N., 1979. Computed medical imaging. Nobel lecture, 8 December 1979.
ICRP, 1991. 1990 Recommendations of the International Commission on RadiologicalProtection. ICRP Publication 60. Ann. ICRP 21, 1-201.
ICRP, 2007a. Managing patient dose in multi-detector computed tomography (MDCT).
ICRP Publication 102. Ann. ICRP 37(1), 1-79.
ICRP, 2007b. The 2007 recommendations of the International Commission on
Radiological Protection. ICRP Publication 103. Ann. ICRP 37, 1-332.
ICRP, 2007c. Radiological Protection in Medicine. ICRP Publication 105. Ann. ICRP
37(6), 1-64.

104

DRAFT REPORT FOR CONSULTATION
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987

IEC, 2009. Medical Electrical Equipment - Part 2-44: Particular Requirements for the
Safety of X-ray Equipment for Computed Tomography. International Standard IEC
60601-2-44. 3rd Edition. International Electrotechnical Commission, Geneva.
Jakobs, T.F., Becker, C.R., Ohnesorge, B., Flohr, T., Suess, C., Schoepf, U.J., Reiser,
M.F., 2002. Multislice helical CT of the heart with retrospective ECG gating:
reduction of radiation exposure by ECG-controlled tube current modulation.
Eur.Radiol. 12, 1081.
Kim, K.P., Einstein, A.J., Berrington de Gonzalez, A., 2009. Coronary artery
calcification screening: estimated radiation dose and cancer risk. Arch. Intern. Med.
169, 1188-1194.
McCollough, C.H., 2008. CT dose: how to measure, how to reduce. Health Physics 95,
508-517.
Miller, J.A., Raichlin, E., Williamson, E.E., McCully, R.B., Pellikka, P.A., Hodge, D.O.,
Miller, T.D., Gibbons, R.J., Araoz, P.A., 2010. Evaluation of coronary CTA
Appropriateness Criteria in an academic medical center. J Am Coll Radiol 7, 125131.
Morin, R.L., Gerber, T.C., McCollough, C.H., 2003. Radiation dose in computed
tomography of the heart. Circulation 107, 917.
Raff, G.L., Chinnaiyan, K.M., Share, D.A., Goraya, T.Y., Kazerooni, E.A., Moscucci,
M., Gentry, R.E., Abidov, A., 2009. Radiation dose from cardiac computed
tomography before and after implementation of radiation dose-reduction techniques.
JAMA 301, 2340-2348.
Sanz, J., Rius, T., Kuschnir, P., Fuster, V., Goldberg, J., Ye, X.Y., Wisdom, P., Poon,M., 2005. The importance of end-systole for optimal reconstruction protocol ofcoronary angiography with 16-slice multidetector computed tomography.
Invest.Radiol. 40, 155.
Schroeder, S., Achenbach, S., Bengel, F., Burgstahler, C., Cademartiri, F., de Feyter, P.,
George, R., Kaufmann, P., Kopp, A.F., Knuuti, J., Ropers, D., Schuijf, J., Tops, L.F.,
Bax, J.J., 2008. Cardiac computed tomography: indications, applications, limitations,and training requirements: report of a Writing Group deployed by the Working
Group Nuclear Cardiology and Cardiac CT of the European Society of Cardiology
and the European Council of Nuclear Cardiology. Eur Heart J 29, 531-556.
Smith-Bindman, R., Lipson, J., Marcus, R., Kim, K.P., Mahesh, M., Gould, R.,
Berrington de Gonzalez, A., Miglioretti, D.L., 2009. Radiation dose associated with
common computed tomography examinations and the associated lifetime attributablerisk of cancer. Arch. Intern. Med. 169, 2078-2086.
Taylor, A.J., Cerqueira, M., Hodgson, J.M., Mark, D., Min, J., O'Gara, P., Rubin, G.D.,
Kramer, C.M., Berman, D., Brown, A., Chaudhry, F.A., Cury, R.C., Desai, M.Y.,
Einstein, A.J., Gomes, A.S., Harrington, R., Hoffmann, U., Khare, R., Lesser, J.,
McGann, C., Rosenberg, A., Schwartz, R., Shelton, M., Smetana, G.W., Smith, S.C.,
Jr.,
2010.
ACCF/SCCT/ACR/AHA/ASE/ASNC/NASCI/SCAI/SCMR
2010
appropriate use criteria for cardiac computed tomography: a report of the American
College of Cardiology Foundation Appropriate Use Criteria Task Force, the Societyof Cardiovascular Computed Tomography, the American College of Radiology, the105

DRAFT REPORT FOR CONSULTATION
3988
3989
3990
3991
3992
3993
3994
3995
3996

American Heart Association, the American Society of Echocardiography, theAmerican Society of Nuclear Cardiology, the North American Society for
Cardiovascular Imaging, the Society for Cardiovascular Angiography andInterventions, and the Society for Cardiovascular Magnetic Resonance. J. Am. Coll.
Cardiol. 56, 1864-1894.

106

DRAFT REPORT FOR CONSULTATION
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038

9. RADIOLOGICAL PROTECTION TRAINING FOR
INTERVENTIONAL FLUOROSCOPY
Main Points
 Interventional cardiologists worldwide typically have little or no training inradiological protection (RP).
 Legislation in most countries requires that individuals who takeresponsibility for medical exposures must be properly trained in RP.
 Training activities in RP should be followed by an evaluation of theknowledge acquired from the training programme (a formal examination
system).
 Physicians who have completed training should be able to demonstrate thatthey possess the knowledge specified by the curriculum by passing anappropriate certifying examination.
 In addition to the training recommended for other physicians who use Xrays, interventionalists, including interventional cardiologists, should receive
a second, higher level of RP training.
 Nurses and other healthcare professionals who assist during fluoroscopic
procedures should be familiar with radiation risks and radiologicalprotection principles, in order to minimise their own exposure and that ofothers.
 Training programmes should include both initial training for all incoming
staff and regular updating and retraining.
 Scientific congresses should include refresher courses on RP, attendance atwhich could be a requirement for continuing professional development

9.1 Introduction(182) Despite the extensive and routine use of x-rays in their clinical practice,interventional cardiologists (IC) worldwide typically have little or no training inradiological protection (RP). Traditionally, medical students do not receive training in RP
during medical school. Medical professionals who subsequently specialise in radiological
specialties, such as diagnostic radiology, nuclear medicine and radiotherapy, are taught
radiological physics and RP as part of their specialty training. In many countries, there isno teaching of RP during training in other specialties, such as medicine and cardiology.
(183) In the past, training in radiological physics and RP was not necessary for nonradiologists, as x-rays and other radiation sources were employed only in radiology
departments, by staff with reasonable training in RP. Although x-ray fluoroscopy has
been in use for more than a century now, its early application involved visualization ofbody anatomy, movement of structures or passage of contrast media through the body.
Radiologists normally performed these procedures. When fluoroscopically guided
interventions were introduced, other specialists (cardiologists and an increasing number
107

DRAFT REPORT FOR CONSULTATION
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048

of clinicians in other medical specialties) began performing these procedures. Initially,
they did so jointly with radiologists, in radiology departments. Over the years, x-ray
equipment was installed in other clinical departments and used by non-radiologists
without radiologist participation. These non-radiologists were not subject to the training
requirements of radiological physics and RP that were mandatory for radiologists. It is
now clear that this training is essential; hence the need for specific guidance for
cardiology.
(184) The Commission has addressed the specifics of training for interventionalists
and nuclear medicine specialists, among others, in ICRP Publication 113 (ICRP 113,
2009). Further information on training in nuclear medicine is presented in Section 7.7.2.

4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081

9.2 Requirements on Radiological protection(185) In its Publications 85 and 113, the Commission recommends a second level ofRP training for interventional radiologists and cardiologists, in addition to the training
recommended for other physicians who use X-rays (ICRP 85, 2000, ICRP 113, 2009).
The Commission also recommends that nurses and other healthcare professionals who
assist during fluoroscopic procedures should be familiar with radiation risks andprecautions, in order to minimise their own exposure and that of others.
(186) Training activities in RP should be followed by an evaluation of the knowledge
acquired from the training programme. Education and training in RP should becomplemented by formal examination systems to test competency before the person isawarded certification. If certification in RP is required for some medical specialties (e.g.
interventional cardiology), certification should be obtained before the professional
practices the specialty.. Training programmes should include both initial training for all
incoming staff and regular updating and retraining. Scientific and professional societies
should contribute to the development of the training syllabuses to ensure a consistent
approach, and to promote and support the education and training. Scientific congresses
should include refresher courses on RP, attendance at which could be a requirement forcontinuing professional development for professionals using ionising radiation. (ICRP
113, 2009).
(187) The International Basic Safety Standards for Protection against Ionising
Radiation and for the Safety of Radiation Sources (BSS), published by the International
Atomic Energy Agency (IAEA) and jointly sponsored by the Food and Agriculture
Organization (FAO), the International Labour Organization (ILO), the Pan American
Health Organization (PAHO) and the World Health Organization (WHO) (IAEA, 1996),
require appropriate training that is sufficient to perform assigned tasks in the conduct of
diagnostic or therapeutic procedures involving radiation.
(188) The Medical Exposure Directive of EC 97/43/Euratom considers interventional
radiology (Article 9) as a special practice involving high doses to patients (EU, 1997).
According to Article 7, Member States shall ensure that the practitioner has adequate
theoretical and practical training for the purpose of radiological practice as well as
relevant competence in radiological protection. No special mention is made ofinterventional cardiology.

108

DRAFT REPORT FOR CONSULTATION
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123

(189) Legislation in most countries requires that individuals who take responsibilities
for medical exposure must be properly trained in RP. However, a training system andaccreditation mechanism is still lacking in many countries.
9.3 Training guidelines, curricula and materials(190) The Commission, in Publication 85 (ICRP, 2000), states that interventional
procedures are complex and demanding and that radiation dose tends to be operator
dependent. It is particularly important that individuals performing these procedures areadequately trained both in clinical techniques and in radiological protection. It further
states that special additional training should be planned when new x-ray systems or
techniques are implemented in a centre. Basic and continuing training in radiologicalprotection should be an integral part of this education. Training requirements are
addressed in Publication 113 (ICRP 113, 2009).
(191) In view of the number of radiation-induced injuries reported in recent years
among patients undergoing interventional procedures (Rehani and Ortiz-Lopez, 2005,
Vano and Gonzalez, 2005, ICRP, 2000, Koenig et al, 2001), a number of organizations
have begun to provide recommendations for training requirements. Published guidelines
were initially for interventional radiologists, but they are gradually becoming available
from cardiology societies.
9.3.1 USA
(192) The Food and Drug Administration (FDA) advisory of 1994 (FDA, 1994)
alerted facilities to ensure proper training. FDA‘s specific recommendations for facilities
in which invasive procedures are performed included the following:Assure appropriate credentials and training for physicians performing
fluoroscopy.
All operators of the system must be trained and understand the operation of thefluoroscopic system, including the implications for radiation exposure from eachmode of operation.
Facilities should ensure that physicians performing fluoroscopic procedures are
educated so that they may, on a case-by-case basis, assess risks and benefits forindividual patients, considering variables such as age, beam location anddirection, tissues in the beam and previous fluoroscopic procedures or radiation
therapy.

(193) In 1995, the American College of Cardiology Cardiac Catheterization
Committee published a Position Statement indicating that appropriate training of staff isimperative, and that ‗‗Proper instruction in the principles of radiation physics and safety
should be a part of every cardiologist‘s education‖ (Brinker et al., 1995). The American

109

DRAFT REPORT FOR CONSULTATION
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158

College of Cardiology Consensus Document further clearly delineated the need for aradiation safety knowledge base for cardiology staff (Limacher et al., 1998).
(194) In 2004, an American College of Cardiology/American Heart Association/
American College of Physicians (ACC/AHA/ACP) Task Force published a further reporton clinical competence and training as a companion to the ACC‘s 1998 report (Hirshfeld
et al, 2004; Limacher et al, 1998). The proposed curriculum in the 2004 document
specifies the knowledge that a qualified physician should possess in order to becredentialed to use x-ray fluoroscopic machines, but does not specify a minimum numberof hours of training. Physicians who have completed training should be able todemonstrate that they possess the knowledge specified by the curriculum by passing anappropriate certifying examination.
(195) The necessary knowledge depth varies, depending upon the types offluoroscopically guided procedures a particular physician performs. The ACC/AHA/ACP
document outlines two different curricula—basic and advanced. The basic curriculum isappropriate for physicians who perform simpler fluoroscopically guided critical-care unit
procedures such as right heart catheterization, temporary pacemaker placement, and intraaortic balloon pump placement. The advanced curriculum is appropriate for physicians
who perform angiographic, interventional, and electrophysiological procedures that
employ greater amounts of radiation in more complex circumstances with different
purposes and a greater attendant risk of patient and personnel injury.
(196) The National Council on Radiation Protection and Measurements (NCRP) in
the U.S. recently published a report on radiation dose management for fluoroscopicallyguided interventional medical procedures (NCRP, 2010). This report makes a number of
specific recommendations, including:

4159
4160
4161
4162
4163
4164
4165
4166

9.3.2 European Commission(197) In compliance with European Commission requirements, an outline for specifictraining in radiological protection for interventional radiology has been developed (EC,
2000; Vañó et al. 1997). Although there is no special mention of interventional
cardiology in the group of professionals, the table giving suggested number of training
hours has a column for interventional cardiology specialists; 20-30 hours of training aresuggested. The initial Spanish experience, based on these guidelines, has been reported(Vañó, 2003). This included development of a training CD (MARTIR, 2002).







Each individual present in a fluoroscopically guided interventional (FGI)
procedure room shall have appropriate radiological protection training.
Every person who operates or supervises the use of FGI equipment shall havecurrent training in the safe use of that specific equipment.
Interventionalists who perform FGI procedures or other procedures with thepotential for high patient doses require additional knowledge and training beyond
that necessary for interventionalists whose practice is limited to low-dose FGI
procedures.
Clinical training and experience is not an acceptable substitute for formal training
in radiation management.

110

DRAFT REPORT FOR CONSULTATION
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179

9.3.3 International Atomic Energy Agency

4180
4181
4182
4183
4184
4185
4186
4187
4188

9.3.4 WHO

4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206

(198) The International Atomic Energy Agency (IAEA) has developed a curriculumwith educational objectives specifically for interventional cardiologists. It is directedprimarily at developing countries where the cardiology professional societies are not yet
sufficiently robust to develop their own separate modules for basic and advanced
curricula in the field of radiological protection. For these countries a ―sandwich‖ module
is ideal, particularly in view of the lack of individuals with sufficient expertise inradiological protection in diagnostic imaging to teach the subject. IAEA has also
prepared educational material in the form of an electronic presentation on CD. This
IAEA training material on Radiation Protection in Cardiology is available without costand can be obtained by writing to patient.protection@iaea.org or downloaded from thewebsite http://rpop.iaea.org.

(199) The World Health Organization (WHO) has stated that specific training ininterventional radiology is required in addition to basic training and has provided training
requirements (WHO 2000). WHO further stated that the training process must becontinued when new techniques are introduced, when new radiological systems are
installed and when new staff are appointed. It also recommended continuous training andrefresher courses at regular intervals. However, interventional cardiology was outside thescope of this document.
9.4 Credentialing(200) There is a distinction between the credentialing of a physician as technicallycompetent to perform a procedure versus the credentialing of the same physician ascompetent to safely use a fluoroscope. Since the amount of radiation employed by theinterventional cardiologist both per patient and annually is no less than that used by aninterventional radiologist, the training standards of radiation physics and radiologicalprotection in interventional cardiology should be the same as for other interventionalists(ICRP 113, 2009).
9.5 References
Brinker, J.A. et al, 1995. Position paper of the American College of Cardiology Cardiac
Catheterization Committee. JACC 26, 319-325.
EU, 1997. Council Directive 97/43 Euratom, on health protection of individuals against thedangers ionizing radiation in relation to medical exposure, and repealing Directive
84/466 Euratom. Official Journal of the European Communities No L 180, 9th July
1997:22-7.
http://europa.eu.int/comm/energy/nuclear/radioprotection/legislation_en.htm

111

DRAFT REPORT FOR CONSULTATION
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250

EC, 2000. Guidelines on education and training in radiation protection for medical
exposures. Radiation Protection 116, European Commission. Directorate General
Environment, Nuclear Safety and Civil Protection. Luxembourg, 2000. Available at:
http://ec.europa.eu/energy/nuclear/radiation_protection/doc/publication/116.pdf
Accessed January 2, 2011.
FDA, 1994. Avoidance of serious x-ray-induced skin injuries to patients during
fluoroscopically-guided procedures. Statement 9 Sept. 1994, Food and Drug
Administration, Rockville, MD, USA.
Hirshfeld, J.W., Jr., Balter, S., Brinker, J.A., Kern, M.J., Klein, L.W., Lindsay, B.D.,
Tommaso, C.L., Tracy, C.M., Wagner, L.K., 2004. ACCF/AHA/HRS/SCAI clinicalcompetence statement on physician knowledge to optimize patient safety and image
quality in fluoroscopically guided invasive cardiovascular procedures: a report of theAmerican College of Cardiology Foundation/American Heart Association/American
College of Physicians Task Force on Clinical Competence and Training. J. Am. Coll.
Cardiol. 44, 2259-2282.
IAEA, 1996. International Basic Safety Standards against Ionizing Radiation and for the
Safety of Radiation Sources, Safety Series No. 115, Vienna: IAEA.
ICRP, 2000. Avoidance of radiation injuries from medical interventional procedures. ICRP
Publication 85, Annals of the ICRP 30 (2).
ICRP, 2009. Radiological protection education and training for healthcare staff andstudents (diagnostic imaging and interventional procedures). ICRP Publication 113.
Ann ICRP 39 (5).
Koenig TR, Wolff D, Mettler FA, Wagner LK. Skin injuries from fluoroscopically guided
procedures: Part 1, Characteristics of radiation injury. AJR 2001; 177: 3-11
Limacher, M.C. et al, 1998. Radiation safety in the practice of cardiology. JACC 31, 892913.
MARTIR (Multimedia and Audiovisual Radiation Protection Training in Interventional
Radiology), 2002. CD-ROM. Radiation Protection 119, European Commission.
Directorate General Environment, Nuclear Safety and Civil Protection. Luxembourg(freeavailabilityat
http://ec.europa.eu/energy/nuclear/radiation_protection/publications_en.htm; go to
publication 119).
NCRP, 2010. Radiation dose management for fluoroscopically guided medical procedures.
Report No. 168. National Council on Radiation Protection and Measurements,
Bethesda, MD.
Rehani, M.M. and Ortiz-Lopez, P., 2006. Radiation effects in fluoroscopically guided
cardiac interventions - keeping them under control. Int. J. Cardiol. 109(2), 147-151.
Vano E, and Gonzalez L. 2005. Accreditation in radiation protection for cardiologists andinterventionalists. Radiat Prot Dosimetry. 117(1-3):69-73.
Vañó, E., Gonzalez, L., Faulkner, K. et al, 1997. Specific training objectives in radiation
protection for medical staff in interventional radiology installations. Draft document.
DIMOND European Concerted Action.
Vañó, E., Gonzalez, L., Canis, M. et el., 2003. Training in radiological protection forinterventionalists. Initial Spanish experience. BJR 76, 217-219.

112

DRAFT REPORT FOR CONSULTATION
4251
4252
4253
4254
4255

WHO, 2000. Efficacy and radiation safety in interventional radiology. World HealthOrganisation, Geneva.

113

DRAFT REPORT FOR CONSULTATION
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297

10. QUALITY ASSURANCE PROGRAMMESMain Points
 Two basic objectives of the radiological protection quality assurance
programme (QAP) are to evaluate patient radiation dose on a periodic basis
and to monitor occupational radiation dose for workers in cardiology facilities
where radiation is used.
 Training in RP (both initial and retraining) should be included in the QAP for
all staff involved in interventional cardiology procedures.
 A cardiologist should be in charge of the QAP aspects of RP for cardiology
procedures, and should be assisted by a medical physicist.
 A senior interventionalist and a medical physicist should be included in theplanning for a new interventional fluoroscopy laboratory, installation of a new
x-ray or nuclear medicine system and the upgrade of existing equipment.
 Periodic evaluation of image quality and procedure protocols should be
included in the QAP.
 The QAP should ensure the regular use of personal dosimeters and include a
review of all abnormal dose values.
 The QAP should establish a trigger level for individual clinical follow-up when
there is a risk of radiation-induced skin injuries.
 Patient dose reports should be produced at the end of procedures, archived
and recorded in the patient’s medical record. If dose reports are not available,
dose values should be recorded in the patient’s medical record together withprocedure and patient identification.
 Patient dose audits (including comparison with DRLs) and reporting areimportant components of the QAP.

10.1

Introduction(201) Quality assurance programs in cardiology should cover all of the planned andsystematic actions necessary to provide confidence that optimum quality has been achievedin the entire diagnostic process, i.e. there is consistent production of adequate diagnostic
information with the lowest acceptable exposure of patients and personnel (WHO 1982).
(202) A quality assurance programme (QAP) for interventional cardiology includes allof the aspects of radiological protection (RP) of patients and staff in addition to the usual
clinical aspects. Only the RP aspects are discussed here. Two basic objectives of the QAP
are to evaluate patient radiation dose on a periodic basis and to monitor occupationalradiation dose for workers in cardiology facilities where radiation is used. Table 10.1
summarizes the 10 key points to be included in a RP QAP. The RP component of the QAP
for interventional cardiology should be an independent portion of the general QAP for xray installations in a particular health centre.

114

DRAFT REPORT FOR CONSULTATION
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340

(203) A cardiologist should be in charge of the QAP aspects of RP for cardiology, andshould be assisted by a medical physicist. The RP QAP for cardiology should be reviewed
at least annually, to allow the opportunity for updates and periodic follow up. Self-audit of
the QAP is also advisable. Table 10.2 presents some questions to be answered as part ofthis internal audit of the QAP.
10.2

Facilities(204) The design of a new interventional fluoroscopy laboratory, the selection andinstallation of a new x-ray or nuclear medicine system and the upgrade of existing
equipment are all complex and expensive processes. Planning for these processes should
include RP. Both a senior physician (interventionalist, nuclear medicine specialist or CT
imaging specialist, as appropriate) and a medical physicist should be included in thisplanning. Physicians representing all of the medical specialties who will be using the newroom should be involved in specifying the equipment for the room. Important aspects toconsider are shown in Table 10.3.
(205) Suggested architectural specifications for catheterization laboratories have been
published by scientific societies (ACC/AHA 1991): adequate dimensions (50 m2), asufficiently large control room with a wide leaded window, sufficient ceiling height (3 m,allowing for ceiling suspended support of the C-arm, monitors, etc.), appropriate radiation
shielding (including window and doors), easy access for personnel and patients, etc. New xray rooms should be of sufficient size to allow personnel to be positioned at a distance fromthe patient when inside the X ray room during the procedures. The installation should
include a control room with a wide shielded glass window, so that other clinicians and otherpersonnel can follow the procedures without radiation exposure.
(206) Appropriate shielding, access to the x-ray room and RP tools (aprons, thyroid
protectors, protective gloves and glasses, protective screens, ceiling-suspended and undertable shields), should be part of the planning for catheterization laboratories.
Dose reduction technology, including the capabilities to measure, record, and transfer
patient dose data to the patient‘s medical record, should be considered an important factor
in the selection of new fluoroscopy and CT equipment. Appropriate standards should betaken into account (IEC 2010).
10.3

Acceptance and constancy testing(207) Acceptance tests shall be made by the company supplying the equipment in thepresence of technical personnel from the centre buying the system, or by centre technicalpersonnel. Commissioning of the new equipment before its clinical use should be theresponsibility of the personnel of the centre.
(208) Periodic quality controls (QC), including dosimeter calibration, should beplanned taking into account international standards, local recommendations and therecommendations of the x-ray system manufacturer. These should also include practicalresults for the appropriate management of patient doses by the cardiologists (e.g. dose rate

115

DRAFT REPORT FOR CONSULTATION
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384

in the different fluoroscopy modes, dose per frame during cine acquisition, CT scan
protocols).
(209) Periodic evaluation of image quality and procedure protocols should also be
included in the QAP. Image quality should be measured with test objects during theacceptance and constancy tests. With the new digital imaging detectors it is possible toselect a wide range of dose values to obtain the required level of quality in the images. It iseasy to specify excessive dose rates, as these do not impair image quality and are not easily
detected from inspection of the image. Cardiologists, in cooperation with the medical
physicist and the industry engineer should set the fluoroscopic or CT system doses toachieve the appropriate balance between image quality and dose.
(210) It is possible to perform this periodic evaluation of image quality using clinicalcriteria. The European consortium DIMOND (DIMOND 2008) has proposed a set ofcriteria to evaluate fluoroscopic cardiac imaging (Bernardi 2001a and 2001b).
(211) Cardiologists should learn the dose required to obtain a certain level ofdiagnostic information. For interventional fluoroscopy, this is related to fluoroscopy time,number of series, number of frames/series, fluoroscopy and cine modes and dose rates,etc.). It is also important to verify that wedge filters, collimation and C-arm angulations areused properly. CT scan protocols, modes, and technique factors, and their effect on patient
dose, are discussed in Chapter 8. Concerns related to nuclear medicine doses are discussed
in Chapter 7.
10.4

Staff

(212) An important aspect of the QAP is a description of the roles and responsibilitiesof personnel. There should be enough staff to avoid an excessive number of procedures per
specialist, and sufficient nursing and technologist support. Support by network specialists(for new digital systems), maintenance and service personnel and medical physics
specialists is advised.
(213) Analysis of staff radiation dose should be included in the QAP. Calibrated
dosimeters for staff must be available. In addition to the dosimeter in the x-ray system forthe evaluation of patient dose, personnel working in the catheterization laboratories shouldwear appropriate dosimeters, and a strict policy for their use should be implemented.
Additional electronic dosimeters may also be useful, especially for RP training of students
and inexperienced personnel. The QAP should ensure the regular use of personal
dosimeters and include a review of all abnormal dose values.
10.5

Training(214) Training in RP is another important item to be included in the QAP. Initialaccreditation in RP should follow local requirements. Special attention to training in RP
should be given to fellows and residents. Seminars to analyse patient and staff dose results
can be an excellent educational tool as well as a useful QA activity. Training is discussed in
more detail in chapter 9 and in ICRP Publication 113 (ICRP, 2009).

116

DRAFT REPORT FOR CONSULTATION
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428

10.6

Follow-up for possible radiation-induced skin injuries for interventional
fluoroscopy procedures(215) The QAP should establish a trigger level for individual clinical follow-up when
there is a risk of radiation-induced skin injuries (ICRP 2000; WHO 2000; NCRP 168). The
Substantial Radiation Dose Level (SRDL) is a threshold value that is used to trigger
additional dose management actions, including patient follow-up (NCRP 2010). There is no
implication that a radiation dose below the SRDL is completely safe or that a radiation dose
above the SRDL will always cause an injury. Some suggested values are a skin dose of 3
Gy, a KAP of 500 Gy·cm2, or an air kerma at the interventional reference point of 5 Gy
(NCRP 168). For cardiology procedures, a KAP between 150 and 250 Gy·cm 2 may be
more appropriate, depending on the radiation field size and the specific protocols. These
values could indicate peak skin doses greater than 2 Gy in a single procedure. These values
are intended to trigger follow-up for a radiation dose that might produce a clinically
relevant injury in an average patient. Lower values may be used at the discretion of the
facility, especially when previously irradiated skin is involved (NCI 2005).
(216) If the trigger level has been exceeded, the patient‘s personal physician should be
informed about the patient‘s radiation dose and the possibility of ionising radiation effects.
Appropriate clinical follow up should be arranged. If the dose estimate after the procedure
is close to the threshold for deterministic effects then the patient should be informed of
possible symptoms or observable skin effects by the interventionist or his/her staff.
Information about what the patient should do in case these effects appear should be
provided.
10.7

Dose audits(217) Patient dose audits and reporting are important components of the QAP. Patient
dose reports should be produced at the end of procedures, archived, and transferred to thepatient‘s medical record. An example of a patient dose report is presented in chapter 5, Fig
5.2. If such reports are not available, dose values should be recorded together with theprocedure and patient identification (Miller et al, 2004). If the reports are available only in
hard copy (printed), relevant data should be transferred to an electronic database for further
analysis. If the reports are available in electronic format, the files should be archived
together with the images. For interventional fluoroscopy, quantities to be measured andrecorded periodically for a significant number of patients include: KAP, reference point air
kerma (if available in the x-ray system), fluoroscopy time, number of series, and number offrames (NCRP, 2010). Reference point air kerma measurement capability has become
widely available in fluoroscopic equipment manufactured after mid-2006. For CT
examinations, the quantities are CTDIw, CTDIvol or DLP (section 8.3). For nuclear
medicine studies, the quantity is administered activity.
(218) Dose audits should include an evaluation of the centre‘s performance withrespect to established reference levels (section 10.7.1). Dose audits for interventional
cardiology procedures require additional analyses (sections 10.7.3, 10.7.4), because theseprocedures also present a risk of deterministic injury.

117

DRAFT REPORT FOR CONSULTATION
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471

10.7.1 Diagnostic Reference Levels(219) Dose guidelines were first introduced in the U.S and the U.K. in the late 1980s
and early 1990s (Wall, 1998).
They were introduced into ICRP recommendations as―investigation levels‖ in Publication 60 (ICRP, 1990) and as ―diagnostic reference levels‖(DRLs) in Publication 73 (ICRP, 1996). DRLs are now an established method of defining
feedback levels for high volume examinations such as chest radiographs or mammograms.
The Commission continues to recommend their use (ICRP 85, ICRP 103, ICRP 105).
(220) DRLs are used to help avoid radiation dose to the patient that does not contributeto the medical imaging task. They provide practitioners with a straightforward tool forcomparing the radiation doses that they deliver to their patients with the radiation dosesdelivered by their colleagues. They are a guide to good practice, but are neither dose limits
nor thresholds that define competent performance of the operator or the equipment. They
are intended to provide guidance on what is achievable with current good practice rather
than optimum performance, and help identify unusually high radiation doses or exposurelevels. A mean dose for a procedure that is less than the reference level does not guaranteethat the procedure is being performed optimally.
(221) To use DRLs as a quality improvement tool, an institution or individual
practitioner collects radiation dose data for cases of a procedure performed in their own
practice. The recommended number of cases varies from 10 to >50, with the latter number
suggested for interventional fluoroscopy procedures because of the high individual
variability in patient dose of cases of image-guided interventional procedures (Wall, 1998,
Vano 2008). The mean radiation dose for the procedure is then compared to the DRL. If
local practice results in a mean radiation dose that is greater than the DRL, the fluoroscopic
equipment should be investigated. If the fluoroscopic equipment is functioning properly
and within specification, operator technique and procedure protocols should be examined(Vano, 2001). Investigations are also appropriate where local values are substantially below
the DRL, as excessively low doses may be associated with poor image quality.
10.7.2 Application of Diagnostic Reference Levels in interventional fluoroscopy
procedures(222) At present, there is little evidence to indicate that dose levels are decreasing ininterventional cardiology. If anything, dose levels are increasing due to the increased
complexity of fluoroscopically guided procedures. As the Commission has noted,
reference levels, in principle, could be useful for dose optimization in interventional
fluoroscopy procedures (ICRP 105). However, patient dose distributions for interventional
fluoroscopy procedures extend over a wide range and are very variable due to the differing
complexity of the procedures, different patient sizes and different operational modes. The
Commission has suggested that a potential approach to this problem is to take into account118

DRAFT REPORT FOR CONSULTATION
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515

the relative ―complexity‖ of the procedure (ICRP 105). Other methods have also been
proposed (NCRP 2010).
(223) Recent studies have provided DRLs for cardiovascular procedures (Peterzol et al
2005, Neofotistou et al 2003, Balter et al 2008, D'Helft et al 2009). Some diagnostic
invasive procedures (e.g., routine coronary angiography) are done in a relatively
standardized way and in sufficient volumes that a valid DRL might be constructed.
(224) The European DIMOND consortium proposed provisional RLs for radiation
doses delivered to patients during two types of invasive cardiology procedures, coronary
angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA). The
proposed DRLs for CA and PTCA were KAP values of 45 Gy·cm2 and 75 Gy·cm2,
fluoroscopy times of 7.5 min and 17 min and 1250 and 1300 frames, respectively. The
consortium concluded that more studies were required to establish "tolerances" from the
proposed levels, taking into account the complexity of the procedure and the patient's size.
(225) Bernardi and co-workers performed studies in Udine, Italy (Bernardi, 2000) andlater in several European hospitals (Neofotistou, 2003), with quantitative assessments ofcomplexity in relation to a patient's exposure to radiation. The relationships between
several clinical factors, anatomic factors and technical factors versus fluoroscopy time were
evaluated for PTCA. A scoring system was developed, and two complexity indexes wereconceived, based on which the procedures were divided into three groups: simple, medium,and complex. The relative complexity of procedures carried out in different centres should
be taken into account when comparing typical patient doses with reference levels.
(226) The IAEA carried out an international project to determine the feasibility of
establishing guidance levels for cardiac catheterization and percutaneous coronary
interventions (IAEA, 2009). The IAEA report has been summarized in a separate
publication (Balter et al, 2008). For PTCA procedures, the report recommended the use of areference level, using KAP, of 100 Gy·cm2 for simple procedures, 125 Gy·cm2 formoderate complexity procedures and 200 Gy·cm2 for complex procedures. Unfortunately,
methods for quantifying complexity have not yet been developed for other interventional
cardiology procedures, such as electrophysiology ablation or pacemaker insertion.
10.7.3 Evaluation of high dose interventional fluoroscopy procedures(227) Reference levels are used to evaluate the average dose per procedure. Because of
the lognormal dose distribution that is characteristic of fluoroscopically guided
interventions, an additional process is needed to evaluate the high dose ―tail‖. The highdose tail is of particular interest, because this tail represents the cases where patient doses
may be high enough to cause deterministic effects.
(228) Cases that required a radiation dose greater than the SRDL (section 10.6) should
be identified and reported to the laboratory director and laboratory quality manager on aperiodic basis. A monthly report is helpful, to ensure that patients with high radiation doses
receive appropriate education and follow-up.
(229) For each such procedure, the report should include patient identifier(s), the dosedelivered during the procedure, the type of procedure, the room in which the procedure was
performed, the operator‘s name, a count of the patient‘s previous invasive procedures

119

DRAFT REPORT FOR CONSULTATION
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536

(essential for estimating total skin dose), and any special notes. The goal of this report is tohelp assure that all patients who received a high radiation dose have been appropriately
educated, and that appropriate follow-up is scheduled and performed (Miller et al, 2010).
(230) Cases resulting in possible radiation injuries should be discussed at the next
laboratory QA meeting. This discussion should include any available diagnoses, planned
patient follow-up, and outcomes. Unless it is clear that the injury was not radiationinduced, the procedure should be reviewed for the appropriate use of radiation in theclinical context (Miller et al, 2010).
10.7.4 Evaluation of skin dose for interventional fluoroscopy procedures(231) It is advisable to measure the skin dose distribution in a sample of patients, toverify that basic aspects of patient protection are being followed (e.g. appropriate
collimation, use of wedge filter, avoidance of a high concentration of radiation fields in thesame skin area). (Vano 1997; Guibelalde 2003). Skin dose may be measured with special
film, with dosimeters placed directly on the patient‘s skin, and by other means (Miller et al,2004). A qualified physicist should be consulted for these measurements.

120

DRAFT REPORT FOR CONSULTATION
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565

Table 10.1. Some key aspects to be included in the section of radiological protection of
the quality assurance programme for cardiac facilities using ionising radiation.

1. Facility design.
2. X ray equipment (selection criteria).
3. Radiological protection tools.
4. Availability of dosimeters.
5. Availability of personnel and their responsibilities.
6. Training in radiological protection (initial and continuing).
7. Patient dose audit and reporting.
8. Clinical follow up for high patient doses
9. Image quality and procedure evaluation.
10. Staff doses.

Table 10.2. Examples of quality indicators
Can your centre report patient dose values from the last year?
Do you have a procedure for the clinical follow-up of high doses to patients?
Do you know the results of your x-ray system QCs?
Are you following your staff dose values?
Do you have a continuous training programme in RP?

121

DRAFT REPORT FOR CONSULTATION
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602

Table 10.3 Facility procurement considerations (ICRP, 2000)
Analysis of clinical needWorkload

Equipment specification

General requirements
Major equipment components
Functional requirements
Specific equipment requirements

Computer capabilities

Image display matrix
Processing times
Memory/image storage
PACS linkages*
HIS linkages†

Systems performance

Image quality
Patient dose
Dose control measures

User manuals

Technical training
Operational training

Compliance with national
and international standards

Electrical safety
Mechanical safety
Radiation safety
Room design/shielding

Service and warranty

Maintenance programme
Quality control programmes
Access to service software protocols/
rationale for service schedules

Operation costs

Cost of consumables - projected over 5 years*PACS=picture archiving and communication system†HIS=hospital information system

122

DRAFT REPORT FOR CONSULTATION
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644

REFERENCES
American College of Cardiology/American Heart Association ad hoc Task Force on
Cardiac Catheterization. ACC/AHA Guidelines for Cardiac Catheterization andCardiac Catheterization Laboratories. JACC 1991; 18 (5): 1149 82.
Balter, S., Miller, D.L., Vano, E., Ortiz Lopez, P., Bernardi, G., Cotelo, E., Faulkner, K.,
Nowotny, R., Padovani, R., Ramirez, A., 2008. A pilot study exploring the possibilityof establishing guidance levels in x-ray directed interventional procedures. Med Phys35, 673-680.
Bernardi G, Padovani R, Morocutti G, Vano E, Malisan MR, Rinuncini M, Spedicato L,
Fioretti PM. Clinical and technical determinants of the complexity of percutaneoustransluminal coronary angioplasty procedures: analysis in relation to radiation
exposure parameters. Catheter Cardiovasc Interv 2000 Sep;51(1):1-9; discussion 10.
Bernardi G, Padovani R, Morocutti G, Spedicato L, Giannuleas JD, Neofotistou E,
Manginas A, Goicolea JC, McNeill J, Vano E, Marzocchi A, Tsapaki V, Fioretti PM,
Malone J. Quality criteria for cardiac images in diagnostic and interventional
cardiology. Br J Radiol. 2001 Sep;74(885):852-5.
Bernardi G, Padovani R, Morocutti G, Spedicato L, Giannuleas JD, Neofotistou E,
Maginas A, Goicolea JC, McNeill J, Vano E. A method based on DIMOND quality
criteria to evaluate imaging in diagnostic and interventional cardiology. Radiat Prot
Dosimetry. 2001;94(1-2):167-72.
D'Helft CJ, Brennan PC, McGee AM, et al. Potential Irish dose reference levels for cardiac
interventional examinations. Br J Radiol 2009; 82:296-302
DIMOND. Available at http://www.dimond3.org/ Last updated October, 2008. Accessed
May 9, 2011.
EC, 2000. Guidelines on education and training in radiation protection for medical
exposures. Radiation Protection 116, European Commission. Directorate General
Environment, Nuclear Safety and Civil Protection. Luxembourg, 2000. Available at:
http://ec.europa.eu/energy/nuclear/radiation_protection/doc/publication/116.pdf
Accessed January 2, 2011.
Guibelalde E, Vano E, Gonzalez L, Prieto C, Fernandez JM, Ten JI. Practical aspects forthe evaluation of skin doses in interventional cardiology using a new slow film. Br J
Radiol. 2003 May;76(905):332-6.
Hirshfeld JW Jr, Balter S, Brinker JA, Kern MJ et al. American College of Cardiology
Foundation; American Heart Association/; HRS; SCAI; American College ofPhysicians Task Force on Clinical Competence and Training. ACCF/AHA/HRS/SCAI
clinical competence statement on physician knowledge to optimize patient safety andimage quality in fluoroscopically guided invasive cardiovascular procedures: a reportof the American College of Cardiology Foundation/American Heart
Association/American College of Physicians Task Force on Clinical Competence andTraining. Circulation. 2005 Feb 1;111(4):511-32.

123

DRAFT REPORT FOR CONSULTATION
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688

IAEA, 2009. Establishing guidance levels in x ray guided medical interventional
procedures: A pilot study. Safety Reports Series No. 59. International Atomic Energy
Agency, Vienna.
IEC, 2010. Medical electrical equipment. Part 2-43: Particular requirements for the safetyof X-ray equipment for interventional procedures. IEC 60601-2-43. 2nd edition.
International Electrotechnical Commission. Geneva, Switzerland.
ICRP, 1990. The 1990 Recommendations of the International Commission on
Radiological Protection. ICRP Publication 60. Ann ICRP 1991; 21(1-3):1-201
ICRP, 1996. Radiological protection and safety in medicine. ICRP Publication 73. Ann
ICRP 26(2):1-47
ICRP, 2000. Avoidance of radiation injuries from medical interventional procedures.
ICRP Publication 85. Ann ICRP 30(2):1-67
ICRP, 2007a. The 2007 Recommendations of the International Commission on
Radiological Protection. ICRP publication 103. Ann. ICRP 37, 1-332.
ICRP, 2007b. Radiological protection in medicine. ICRP Publication 105. Ann ICRP
37:1-63.
ICRP, 2009. Radiological protection education and training for healthcare staff andstudents (diagnostic imaging and interventional procedures). ICRP Publication 113.
Ann ICRP 39 (5).
Miller, D.L., Balter, S., Wagner, L.K., Cardella, J.F., Clark, T.W.I., Neithamer, C.D., Jr.,
Schwartzberg, M.S., Swan, T.L., Towbin, R.B., Rholl, K.S., Sacks, D., 2004. Quality
improvement guidelines for recording patient radiation dose in the medical record. J
Vasc Interv Radiol 15, 423-429.
Miller DL, Balter S, Schueler BA, Wagner LK, Strauss KJ, Vano E. Clinical radiation
management for fluoroscopically guided interventional procedures. Radiology 2010;
257(2):321-332.
NCI. Interventional fluoroscopy: reducing radiation risks for patients and staff. NIH
Publication No. 05-5286. Bethesda, MD: National Cancer Institute, 2005. Availableat:
http://www.cancer.gov/images/Documents/45bae965-697a-4de8-9daeb77222e0e79d/InterventionalFluor.pdf Accessed January 1, 2011.
Neofotistou V, Vano E, Padovani R, et al. Preliminary reference levels in interventional
cardiology. Eur Radiol 2003; 13:2259-2263.
NCRP, 2010. Radiation dose management for fluoroscopically guided medical procedures.
NCRP Report No. 168. National Council on Radiation Protection and Measurements,
Bethesda, MD.
Padovani R, Bernardi G, Malisan MR, Vano E, Morocutti G, Fioretti PM. Patient dose
related to the complexity of interventional cardiology procedures. Radiat Prot
Dosimetry. 2001;94(1-2):189-92.
Peterzol A, Quai E, Padovani R, Bernardi G, Kotre J, Dowling A. Reference levels in
PTCA as a function of procedure complexity. Radiat Prot Dosimetry 2005; 117(1-3);
54-58.
Vano E, Guibelalde E, Fernandez JM, Gonzalez L, Ten JI. Patient dosimetry ininterventional radiology using slow films. Br J Radiol. 1997 Feb;70:195-200.

124

DRAFT REPORT FOR CONSULTATION
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700

Vano E, Gonzalez E. Approaches to establishing reference levels in interventional
radiology. Radiat Prot Dosim 2001; 94:109-112.
Vano E, Gonzalez L, Canis M, Hernandez-Lezana A. Training in radiological protection
for interventionalists. Initial Spanish experience. Br J Radiol. 2003 Apr;76(904):217-9.
Vano E, Järvinen H, Kosunen A, et al. Patient dose in interventional radiology: a European
survey. Radiat Prot Dosimetry 2008; 129:39-45.
Wall BF, Shrimpton PC. The historical development of reference doses in diagnostic
radiology. Radiat Prot Dosimetry 1998; 80:15-19.
WHO, 1982. Quality Assurance in Diagnostic Radiology. Geneva.
WHO, 2000. Efficacy and Radiation Safety in Interventional Radiology. Geneva.
4818-2733-7736, v. 3125